18-letter words containing a, m, p, h, o
- pygmy hippopotamus — a small hippopotamus, Choeropsis liberiensis, of forests and swamps in western Africa.
- 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
- southampton island — an island in N Canada, in the Northwest Territories at the entrance to Hudson Bay. 19,100 sq. mi. (49,470 sq. km).
- 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
- withdrawal symptom — effects of stopping a drug
- world championship — an international competition in a particular sport or activity for people all around the world