18-letter words containing m, o, p, h, e, a
- palmer archipelago — a group of islands in the South Atlantic Ocean, off the NW coast of the Antarctic Peninsula.
- pathname separator — (file system) The character used to separate elements of a path or pathname. Under Unix and POSIX.1 compliant systems the pathname separator is the (forward) slash, in MS-DOS backslash serves the same purpose. For obvious reasons the no directory or file name can contain this character.
- peppermint camphor — menthol.
- 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.
- photoisomerization — isomerization induced by light.
- phytohemagglutinin — a lectin, obtained from the red kidney bean, that binds to the membranes of T cells and stimulates metabolic activity, cell division, etc.
- policeman's helmet — a Himalayan balsaminaceous plant, Impatiens glandulifera, with large purplish-pink flowers, introduced into Britain
- potassium chlorate — a white or colorless, crystalline, water-soluble, poisonous solid, KClO 3 , used chiefly as an oxidizing agent in the manufacture of explosives, fireworks, matches, bleaches, and disinfectants.
- potassium chloride — a white or colorless, crystalline, water-soluble solid, KCl, used chiefly in the manufacture of fertilizers and mineral water, and as a source of other potassium compounds.
- potassium sulphate — a soluble substance usually obtained as colourless crystals of the decahydrate: used in making glass and as a fertilizer. Formula: K2SO4
- pound the pavement — a paved road, highway, etc.
- processionary moth — a moth of the family Thaumetopoeidae, esp the oak processionary moth (Thaumetopoea processionea), the larvae of which leave the communal shelter nightly for food in a V-shaped procession
- programmer's cheer — (humour) "Shift to the left! Shift to the right! Pop up, push down! Byte! Byte! Byte!" [Origin?]
- projection machine — an apparatus that projects motion pictures; projector.
- propaganda machine — the group of people, publications, etc, such as of a government, country etc, responsible for the organized dissemination of information, allegations, etc, to assist or damage the cause of a government, movement, etc
- provision merchant — a person or company in the business of retailing food and other provisions
- psychogalvanometer — a type of galvanometer for detecting and measuring psychogalvanic currents.
- pyromucic aldehyde — furfural.
- segmental phonemes — phonemes consisting of sound segments; hence, the vowel, consonant, and semivowel sounds of a language
- september holidays — a period of time in September when people do not have to go to school, college or work
- something to spare — a surplus of something
- spherical geometry — the branch of geometry that deals with figures on spherical surfaces.
- symphony orchestra — a large orchestra composed of wind, string, and percussion instruments and organized to perform symphonic compositions.
- systematic phoneme — a phonological unit in generative phonology representing an underlying form that takes into account the relationship between phonological patterns and morphological variation, as the unit underlying the second vowel in both derive and derivative.
- temporary hardness — hardness of water due to the presence of magnesium and calcium hydrogencarbonates, which can be precipitated as carbonates by boiling
- the family compact — the ruling oligarchy in Upper Canada in the early 19th century
- the lords temporal — (in Britain) peers other than bishops in their capacity as members of the House of Lords
- the palmetto state — a nickname for South Carolina