18-letter words containing t, o, s, l
- offset lithography — offset (def 6).
- oil of catechumens — holy oil used in baptism, the ordination of a cleric, the coronation of a sovereign, or in the consecration of a church.
- old curiosity shop — a novel (1840–41) by Dickens.
- old man of the sea — (in The Arabian Nights' Entertainments) an old man who clung to the shoulders of Sindbad the Sailor for many days and nights.
- on one's last legs — either of the two lower limbs of a biped, as a human being, or any of the paired limbs of an animal, arthropod, etc., that support and move the body.
- on the danger list — critically ill in hospital
- one's heart bleeds — used to express sympathetic grief, but often used ironically
- operationalisation — Alternative spelling of operationalization.
- optical disc drive — optical disk drive
- optical disk drive — (hardware) (Or "optical disc drive", "optical storage") A generic term for any device that reads and/or writes optical media, i.e. compact discs, DVDs and/or Blu-ray discs or future media that uses light (from a small laser) to read data off a removable, rotating disk. At least one such drive is commonly installed in most personal computers to allow them to play and/or record audio and video media and load and store data such as program installers. The floppy disk has been replaced by optical media due to its vastly greater capacity, e.g. 50,000 megabytes for a dual-layer blu-ray disc compared with 1.5 megabytes for a floppy (over 30,000 times as much).
- optical microscope — traditional magnifying instrument
- optical soundtrack — the final soundtrack on a motion picture, which appears as a band of black and white serrations along a strip of film to the left of the composite print. Light is shined through the serrations and is converted to audible sound.
- order of australia — an order awarded to Australians for outstanding achievement or for service to Australia or to humanity at large; established in 1975
- organic solidarity — social cohesiveness that is based on division of labor and interdependence and is characteristic of complex, industrial societies.
- oriental alabaster — alabaster (def 2).
- oriental cat's-eye — a chatoyant variety of chrysoberyl, used as a gem.
- oriental scops owl — any of a group of small owls having ear tufts and a whistling call, especially Otus scops (Old World scops owl) and O. sunia (Oriental scops owl)
- oriental shorthair — any of a breed of domestic cat, similar to the Siamese but with greenish eyes and often a coat of a solid color
- oscillating engine — a steam engine having piston rods connected directly to the crankshaft and cylinders oscillating on trunnions.
- out of one's skull — foolish; silly
- overspecialization — excessive specialization, as in a field of study.
- owen stanley range — a mountain range in SE New Guinea. Highest peak: Mount Victoria, 4073 m (13 363 ft)
- pair of spectacles — a score of 0 in each innings of a match
- paleoclimatologist — the branch of paleogeography dealing with the study of paleoclimates.
- parathyroid glands — any of several small oval glands usually lying near or embedded in the thyroid gland.
- passing modulation — a modulation of a temporary nature.
- payload specialist — an astronaut trained to handle highly complex or classified equipment carried aboard a space shuttle and to conduct experiments in space.
- peano's postulates — a collection of axioms concerning the properties of the set of all positive integers, including the principle of mathematical induction.
- pectoral sandpiper — an American sandpiper, Calidris melanotos, the male of which, when courting, inflates its chest conspicuously.
- pellitory of spain — a small Mediterranean plant, Anacyclus pyrethrum, the root of which contains an oil formerly used to relieve toothache: family Asteraceae (composites)
- personal assistant — aide
- personal exemption — Your personal exemption is the amount of money that is deducted from your gross income before you have to start paying income tax.
- phanerocrystalline — (of a rock) having the principal constituents in the form of crystals visible to the naked eye.
- phantasmagorically — having a fantastic or deceptive appearance, as something in a dream or created by the imagination.
- phosphatidylserine — any of a class of phospholipids occurring in biological membranes and fats
- photochemical smog — air pollution containing ozone and other reactive chemical compounds formed by the action of sunlight on nitrogen oxides and hydrocarbons, especially those in automobile exhaust.
- physical education — systematic instruction in sports, exercises, and hygiene given as part of a school or college program.
- physical inventory — To carry out a physical inventory is to count all the stock on hand.
- pilotless aircraft — an aircraft equipped for operation by radio or by robot control, without a human pilot aboard; drone.
- pilotless ignition — a system for igniting a gas burner, as in a gas range, furnace, or boiler, without the use of a pilot light.
- plate-glass window — a window that has glass which has been formed by rolling
- play cat and mouse — Also called cat and rat. a children's game in which players in a circle keep a player from moving into or out of the circle and permit a second player to move into or out of the circle to escape the pursuing first player.
- plight one's troth — to make a promise of marriage
- point set topology — topology (def 2).
- policeman's helmet — a Himalayan balsaminaceous plant, Impatiens glandulifera, with large purplish-pink flowers, introduced into Britain
- political prisoner — sb imprisoned for political dissidence
- political question — a question regarded by the courts as being a matter to be determined by another department of government rather than of law and therefore one with which they will not deal, as the recognition of a foreign state.
- polynesian tattler — a sandpiper, H. incanus, native to the Pacific coastal regions
- polystyrene cement — a purpose-made adhesive for fixing rigid polystyrene
- population density — ratio: inhabitants to area