FRUSTULE Meaning of FRUSTULE in English [ 'frʌstju:l ]■ noun Botany the silicified cell wall of a diatom, consisting of two valves or overlapping halves.OriginC19: from L. frustulum , dimin. of frustum (see frustum ). Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004