Obeah
Oboe
Obsidian
Ocarina
Occlusion
Octroi
Ode
Ohm
Ohm's law
Oil
Old Maid
Olefines
Oleic acid
Oligarchy
Oligocene
Olpe
Olympic Games
Omber
Omega
Omega-minus particle
Omelette
Omnibus
Oncology
Ondograph
Oneg Shabbat
Opera
Ophicleide
Opium
Optophone
Order of the Garter
Ordovician
Organic
Organic Chemistry
Origami
Ormolu
Ornithology
Orris Root
Orthicon
Ortho-Toluidine
Osmiridium
Osmium
Ounce
Ounces
Overcoil
Oxalic acid
Oxidation
Oxidise
Oxygen
Oxytocin
Ozone
P Band
Pacemaker
Pack-Fong
Packet
Packet Switched Network
Packet Switching
Pahari
Palaeocene
Palaeography
Palaeontology
Pali
Palindrome
Palladium
Palm Kernel Oil
Palm Oil
Palmitic Acid
Pampas
Pancratium
Pantothenic acid
Pantoum
Para-cresol
Paracetamol
Paradichlorobenzene
Paraffin
Parallax
Parallel Transmission
Parchment
Parity
Parity Bit
Parity Check
Parsec
Pasteurisation
Patten
Pcp
PDS
Peat
Peck
Pentaerythritol Tetranitrate
Pentagon
Pentathlon
Pentode
Pentose
Penumbra
Perception
Percolator
Pericarp
Pericarps
Perigee
Perigynous
Perikon Detector
Permafrost
Permaid
Permalloy
Permanganate
Permian
Persimmon
Peruke
Pessary
Petrol
Petroleum
Pewter
pH
Phencyclidine
Phenol
Phenyl benzene
Phenyl salicylate
Phenylacrylic Acid
Phocine
Phon
Phosphate
Phosphorus
Phot
Photon
Photosynthesis
Phototropic
Obeah is a form of witchcraft practised in the Caribbean.
The oboe is a musical instrument of the woodwind family.
Obsidian is volcanic glass.
The ocarina is a small wind instrument consisting of a pipe pierced with holes for the fingers. They are usually made of terra-cotta, but sometimes of metal.
Occlusion is the property possessed by certain solids, notably some metals, of retaining gases either within the solid or on the surface. There is no chemical combination in the accepted sense.
An octroi is a station at the entrance of a town or department for the collection of local dues and tariffs within a country.
An ode is a short poem, frequently of irregular or complicated lyrical form, usually written for some special occasion. The term was originally applied to the choric songs of the Greek dramas, and also to the poems of Pindar, Sappho, Horace etc.
The ohm is the SI unit of electrical resistance. It was originally defined with reference to the resistance of a column of mercury, but is now taken as the resistance between two points when a potential difference of one volt between them produces a current of one ampere.
Ohm's law is that the steady current in a metal circuit is directly proportional to the constant total electromotiveforce in the circuit, that is e/i = r
Oil is a large group of viscid liquids which have a characteristic smooth and sticky feel, are lighter than water, are inflammable and chemically neutral.
Old Maid is a card game for any number of players. A full deck of 52 cards is used from which the Queen of Hearts has been removed and the remainder dealt. Pairs are discarded and remaining cards are passed face down to the player to the left who picks one at random. Play continues untill all cards have been played and one player is left holding the odd Queen (the Old Maid).
Olefines are unsaturated hydrocarbons of the aliphatic series. They resemble the parrafins but chemically they are more reactive. Methylene is an example of a very reactive olefine.
Oleic acid is a colourless, odourless liquid unsaturated acid with the formulae C18H34O2. It is obtained from animal tallow and natural vegetable oils in which it occurs as the glycerol ester. It is chiefly used in the manufacture of soap, commercial oleates and cosmetics.
Oligarchy is government by a limited number of persons, as distinct from democracy (government by all classes) and monarchy (government by one person).
The Oligocene was the fifteenth geological period, 42,000,000 years ago.
An olpe is a Greek oil-flask or small jug for storing oil.
The Olympic Games originated at Olympia, in Elis, Peloponnesus and were said to have been originated by Hercules in honour of the Olympian Zeus, and to have been revived by Iphitus in 776 BC. Thereafter they were held every 4 years without a break until 393. Today the Olympic Games are still held every 4 years and are a general sporting contest held between supposedly amateur athletes of all countries. In recent years the amateur status of many athletes from larger and more industrial countries has become very dubious casting a shadow over the spirit of the games.
Omber was a popular card game played in the 17th and 18th centuries. It was played by three persons and with 40 cards.
Omega is the 24th and last letter of the Greek alphabet.
In physics, an omega-minus particle is a baryon with strangeness -3, isotopic spin 0, and negative charge.
An omelette is a dish of eggs beaten until frothy and cooked until set in a frying pan. Often other ingredients, such as mushrooms or cheese are added.
Omnibus (latin for ''for all'') is the old term for a bus (public passenger carrying vehicle). The first modern bus to make regular journeys was first introduced in Paris in 1828 and introduced to London by Shillibeer in 1829 when one carrying 22 passengers ran from Paddington to the Bank.
Oncology is the branch of medicine dealing with tumours and cancer including the origin, development, diagnosis and treatment of malignant neoplasms.
An ondograph is an instrument for graphically recording oscillatory variations, as in alternating current.
Oneg Shabbat is a Jewish celebration in honour of the Sabbath that takes place on Friday evening or Saturday afternoon and usually includes a programme of songs, a lecture and refreshments.
Opera is a stage entertainment consisting of a play sung to music in its entirety, with no spoken dialogue at all. Opera originated in Italy around 1600 and has subsequently spread throughout the world.
The ophicleide was a brass musical instrument, now replaced by the brass tuba.
Opium is a drug extracted from the seeds of the opium poppy.
The optophone is an instrument invented by Fournier d'Albe, by means of which the letters of ordinary print are caused to produce characteristic musical sounds by being projected optically on to a screen composed of a number of selnium cells connected to an AC electrical source of audio frequency, and to a loud speaker.
The Order of the Garter is a dignitary awarded for chivalry. It was implemented in 1349.
The Ordovician period was the fourth geological period, 375,000,000 years ago.
In chemistry, the term organic refers to substances which occur naturally as constituents of organised bodies.
Organic chemistry is the chemistry of the compounds of carbon.
Origami is the art of paper folding.
Ormolu is an alloy of brass used in making candlesticks, small statues and other articles. The composition is generally 58 per cent copper, 26 per cent zinc and 16 per cent tin.
Ornithology is the scientific study of birds.
Orris root is the powdered root of Iris florentina, the common white flowered iris. It was used in making perfume before the advent of synthetic scents.
An orthicon is a form of television camera tube in which the optical image to be transmitted is projected on a photo-sensitive mosaic on the far side of a transparent signal plate, a charge pattern thus being produced on the mosaic.
Ortho-Toluidine is a form of toluidine used in the manufacture of rosaniline.
Osmiridium (iridosmine) is a naturally occuring alloy of osmium and iridium.
Osmium is a blue-white metal element with the symbol Os. It is volatile and very poisonous.
The ounce is a unit of measurement of the avoirdupois scale equivalent to 16 drams or 28.350 grams.
see "ounce"
In clock and watch making an overcoil is a fixed end of a spiral hairspring, consisting of an upwardly and inwardly bent continuation of the outermost coil of the spring and used to offset the asymmetry of the common spiral spring when tight, which impairs isochronism.
Oxalic acid is a poison found in rhubarb.
Oxidation is the chemical combination of atoms with oxygen atoms to form oxides. In metals, the process appears as rust, iron rust being iron oxide, a molecule formed of iron atoms combined with oxygen atoms.
The term oxidise refers to the chemical reaction of oxidation.
Oxygen is a gaseous element with the symbol O that is partly soluble in water. It is the only gas able to sustain respiration.
Oxytocin is a hormone that stimulates the uterus in late pregnancy to initiate and sustain labour.
Ozone is a blue gas. The molecules are comprised of three oxygen atoms.
The P band is the frequency band from 225 to 390 mhz employed in radar.
A pacemaker is an electronic device that stimulates the heart muscles by delivery small electric shocks to it.
see "Nickel Silver"
In the sense of communications, a packet is a structured group of binary digits in a prearranged sequence containing synchronism, address, control an error-checking data. Specialised synonym for a ''block'' of data in CCITT Packet Data Network standards.
A Packet Switched Network is a network dedicated to the routing and delivery of data put in the form of standardised ''packets.''
Packet Switching is the technique in which a stream of data is broken into standardised units called ''packets,'' each of which contains address, sequence, control, size and error checking information in addition to the user data. Specialised packet switches operate on this added information to move the packets to their destination in the proper sequence and again present them in a contiguous stream.
Pahari is a language with a number of different dialects spoken from the Punjab to Nepal along the southern spurs of the Himalayas.
The Palaeocene was the thirteenth geological period, 80,000,000 years ago.
Palaeography is the study of ancient manuscripts written on papyrus, parchment or similar material, as distinct from epigraphy which is the study of ancient inscriptions incised on hard materials such as wood, stone or metal.
Palaeontology is a branch of biology and geology which deals with fossils. It is divided into palaeozoology and palaeobotany, which respectively have animals and plants as their subject matters.
Pali is an old language related to Sanskrit, in which the Buddhist classical literature was written.
A palindrome is a word, phrase or sentance the letters of which read the same left to right as right to left, such as ''was it a cat I saw''.
Palladium is a rare grey-white metal element with the symbol Pd. It has the power of absorbing a very large amount of hydrogen to which it is permeable when heated. It is used in an alloy with gold in dentistry and jewellery. In its pure form it is used for making watch springs and mirrors.
Palm kernel oil is a fatty oil obtained from the kernels of the palm fruit and used in the manufacture of soap and margarine.
Palm oil is a fatty oil obtained from the pericarp of the palm fruit and used in the manufacture of soap and edible fat.
Palmitic acid is a widely distributed naturally occuring fatty acid with the formula C16H32O2.
The pampas are natural grasslands of South America.
A pancratium is an athletic contest in wrestling and boxing.
Pantothenic acid is a hydroxy acid found in plant and animal tissues that is one of the vitamin B complex of substances and is used for cell growth.
A pantoum is a Malay verse consisting of an indefinite number of quatrains with the second and fourth lines of each quatrain repeated as the first and third lines of the following one.
Para-cresol is a cresol found in bad eggs.
Paracetamol is an analgesic. Over doses of paracetamol can cause liver damage.
Paradichlorobenzene is a white crystalline, volatile substance which is insoluble in water of the benzene series. It has a penetrating odour and is used chiefly as a moth repellent.
Paraffin is a family of hydrocarbons.
The term parallax describes the apparent movement of an object when viewed from two different positions.
Parallel Transmission is the simultaneous transmission of all parts of a signal at one time; in data transmission, requiring a separate signal path for each of the bits of a character; internal to computers, this is called a ''parallel bus.''
Parchment is a type of fine writing paper traditionally made from sheep or goat skin.
In communications systems and computers, parity is a constant state of equality; one of the oldest and simplest methods of error checking data transmission. Characters are forced into parity (total number of marking bits odd or even as selected by choice) by adding a one or zero bit as appropriate when transmitted; parity is then checked as odd or even at the receiver.
A Parity Bit is a check bit appended to an array of binary digits to make the sum of all the digits always odd or always even.
Parity Check is a checking method that determines if the sum of all the digits in an array is odd or even.
A parsec is an astronomical unit of distance equivalent to 3.2616 light years.
Pasteurisation is a preservative heat treatment applied to foods, notably milk.
Patten is another name for a clog.
Pcp is an abbreviation for phencyclidine.
PDS is an abbreviation for Portable Diagnostic System. It is an expert system which diagnoses faults in machinery from information received from sensors connected to the machinery. Sensor readings are compared with known data about component malfunction symptoms to diagnose faults.
Peat is a fibrous organic compound found in bogs that is formed by the partial decomposition of plants.
The peck is a unit of capacity measurement equivalent to 2 gallons or 9.092 litres.
Pentaerythritol Tetranitrate is an anti-anginal drug used to reduce
the frequency and severity of angina attacks.
A pentagon is a five sided regular polygon.
The pentathlon is a five sport competition.
A pentode is an electronic amplifying valve with 5 main electrodes.
A pentose is a sugar with 5 carbon atoms in the molecule.
A penumbra is a partly shaded region around the shadow of an opaque body. The term is especially applied to describe the partly shaded region around a total eclipse of the sun or moon.
Perception is the ability to observe and understand, particularly intuitively.
A percolator is a device for making coffee by allowing water to filter repeatedly through ground coffee.
The pericarp is the wall of the ripened ovary of a plant.
see "Pericarp"
Perigee is an astronomical term referring to the position in the Moon's orbit nearest to the earth, opposite to Apogee.
A perigynous plant is one which has stamens situated around the pistil or ovary.
A Perikon Detector was a form of crystal detector employed in the early days of radio broadcasting. It consisted of a crystal of zincite and a crystal of bornite so mounted that there was a point contact between them.
Permafrost is the permanently frozen subsoil in Arctic regions.
Permaid is an expert system, developed at Honeywell for trouble shooting large disk drives.
Permalloy is a nickel steel alloy, containing about 78 percent nickel. It is characterised by a very high permeability in low magnetic fields. It is extensively used in submarine cables.
A permanganate is any salt of permanganic acid.
The Permian was the eighth geological period, 205,000,000 years ago. It marked the evolution of the reptiles.
The persimmon is a yellow-orange plum-like astringent fruit. It becomes sweet when softened by frost.
A peruke was a man's wig of the 17th and 18th centuries. It was usually powdered and gathered at the back of the neck with a ribbon.
A pessary is a vaginal suppository.
Petrol is a volatile, flammable liquid mixture of hydrocarbons, obtained from petroleum and used as a fuel for internal-combustion engines.
Petroleum is an oily, thick, flammable, usually dark coloured liquid that is a form of bitumen or a mixture of various hydrocarbons, occurring naturally in various parts of the world and often separated by distillation into petrol, naphtha, benzene, kerosene and paraffin.
Pewter is an alloy of tin and lead.
pH is a mesurement of acidity or alkalinity in terms of hydrogen ion content.
Phencyclidine is an illegal drug also known as angel dust.
Phenol is a compound derived from coal-tar and used in the manufacture of nylon.
Phenyl benzene is a colourless crystalline organic compound. It can be made by passing benzene through a red-hot tube, when condensation takes place with the formation of phenyl benzene. It also occurs in coal-tar, and it is used in organic syntheses.
see "Salol"
see "Cinnamic Acid"
Phocine is a zoological term pertaining to seals.
The phon is the unit of loudness.
A phosphate is any salt of phosphorus oxy acids.
Phosphorus is a non-metallic element with the symbol P.
A phot is a unit of luminous flux equal to the illumination produced by one lumen on a surface of one square centimetre.
A photon is a light quantum, that is a definite amount of radiation having a frequency within the visible spectrum. A photon is emitted from an excited atom when one of the orbital electrons, having been transferred to an orbit of higher energy level, suddenly returns to its former orbit.
Photosynthesis is the process by which plants convert carbon dioxide into carbohydrates by chlorophyll under the influence of light.
Something which is phototropic seeks light. The term is used in Biology to describe animalcules which seek the light.