English

hemipentahydrate

From hemi- + pentahydrate.

Proto-Indo-European *sem- ‘one, whole’

Proto-Indo-European *sēmi ‘half’

English hemi-

Today it means

noun A solid that has five molecules of water of crystallisation for each two unit cells

Language periods are conventional ranges, not dates for this word.

Etymograph / hemipentahydrate