avail
v.
c.1300, availen, apparently a French compound formed in English from Old French a- "to" (see ad-) + vailen "to avail," from vaill-, present stem of valoir "be worth," from Latin valere (see valiant). Related: Availed; availing. As a noun, from c.1400.
〔李〕[a-(ad-);vail] v.有益于，有利于，有助于 ←val,vail (L valere,valitum)=to be worth or strong 价值，强壮