18-letter words containing h, a, p, y, m
- september holidays — a period of time in September when people do not have to go to school, college or work
- spherical geometry — the branch of geometry that deals with figures on spherical surfaces.
- sympathetic strike — sympathy strike.
- sympathetic string — a thin wire string, as in various obsolete musical instruments, designed to vibrate sympathetically with the bowed or plucked strings to reinforce the sound.
- 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
- withdrawal symptom — effects of stopping a drug