The Collaborative International Dictionary
Berain
Berain \Be*rain\, v. t. [imp. & p. p. Berained; p. pr. & vb.
n. Beraining.]
To rain upon; to wet with rain. [Obs.]
--Chaucer.
Wiktionary
berain
vb. (context transitive English) To rain upon; wet with rain; moisten.