Word Study
frustule
CIDE DICTIONARY
frustule, n. [L. frustulum, dim. fr. frustum a piece: cf. F. frustule.].
The siliceous shell of a diatom. It is composed of two valves, one overlapping the other, like a pill box and its cover. [1913 Webster]
OXFORD DICTIONARY
frustule, n. Bot. the siliceous cell wall of a diatom.
Etymology
F f. L frustulum (as FRUSTUM)
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