1. fermentum — de Vaan
fermentum 'ferment; yeast' [η. ο] (Ρ1-+) Derivatives\fermentare 'to cause fermentation' (Varro+). Pit. *fer(a)mentom. PIE *bher(H)-mn [n.J 'ferment'. IE cognates: OE beorma, MLG barme, NHG Burme 'barm\ Form and meaning of the original root are not clear. Semantically, it is most attractive to regard fermentum as a derivative of the primitive root *bhr(H)- underlying the extended root *bhrH-u- or or *bhr-u- 'to boil' … — [de Vaan, s.v. fermentum, p. 227]