18-letter words containing o, p, i, s
- 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.
- 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)
- orthopedic surgery — corrective operation on bones or joints
- oscillographically — By means of oscillography.
- outer automorphism — an automorphism that is not an inner automorphism.
- overpressurization — pressure in excess of normal atmospheric pressure, as that caused by an explosion's shock wave or created in an accelerating airplane.
- overprotectiveness — unduly protective.
- overrepresentation — to give too much representation to; represent in numbers that are disproportionately high.
- overspecialization — excessive specialization, as in a field of study.
- ox-tongue partisan — a shafted weapon having a long, wide, tapering blade.
- pacinian corpuscle — (sometimes lowercase) a microscopic, onionlike body consisting of layers of connective tissue wrapped around a nerve ending, located in the deep layers of skin, tendons, etc., and functioning as a sensory receptor of pressure and vibration.
- packet switch node — (PSN) A dedicated computer whose purpose is to accept, route and forward packets in a packet-switched network.
- pair of spectacles — a score of 0 in each innings of a match
- pairs championship — an event in a sport such as tennis or darts open to pairs of competitors
- 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.
- passing-out parade — a ceremonial parade of cadets who have completed their training
- passive vocabulary — all the words, collectively, that a person can understand
- payload specialist — an astronaut trained to handle highly complex or classified equipment carried aboard a space shuttle and to conduct experiments in space.
- peasant proprietor — a peasant who owns land, especially the land he or she tills.
- 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)
- pensioneer trustee — (in Britain) a person authorized by HMRC to oversee the management of a pension fund
- percussion flaking — a method of forming a flint tool by striking flakes from a stone core with another stone or a piece of bone or wood.
- percussion section — orchestra, group: drums, etc.
- percussion welding — a form of resistance welding in which the required pressure is provided by a hammerlike blow.
- perfect continuous — perfect progressive.
- performance artist — an artist that is involved in a theatrical presentation that incorporates various art forms, such as dance, sculpture, music, etc
- perish the thought — to die or be destroyed through violence, privation, etc.: to perish in an earthquake.
- pernicious anaemia — Pernicious anaemia is a very severe blood disease.
- 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.
- personal insurance — insurance on personal risk, such as car insurance, health insurance or loss of earnings insurance
- personal organizer — a small notebook with sections for personal information, as dates and addresses.
- pescadores-islands — (used with a plural verb) Penghu.
- peter tschaikowsky — Peter Ilyich [il-yich] /ˈɪl yɪtʃ/ (Show IPA), Tchaikovsky, Peter Ilyich.
- peters' projection — a form of modified world map projection that attempts to reflect accurately the relative surface areas of landmasses, an approach which gives greater prominence (than do standard representations) to equatorial countries
- petite bourgeoisie — the portion of the bourgeoisie having the least wealth and lowest social status; the lower middle class.
- 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.
- philosophy of life — any philosophical view or vision of the nature or purpose of life or of the way that life should be lived.
- phosphatidylserine — any of a class of phospholipids occurring in biological membranes and fats
- phosphonium iodide — a colorless to slightly yellowish, crystalline, water-soluble solid, PH 4 I, used in chemical synthesis.
- 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.
- photodecomposition — the breaking down of molecules by radiant energy.
- photoisomerization — isomerization induced by light.
- photomorphogenesis — plant development that is controlled by light.
- photosensitization — to make (a material) photosensitive, as by the application of a photosensitive emulsion.
- physical education — systematic instruction in sports, exercises, and hygiene given as part of a school or college program.