late 14c., from Old French adherent or directly from Latin adhaerentem (nominative adhaerens), present participle of adhaerere "stick to," from ad- "to" (see ad-) + haerere "to stick" (see hesitation).

"follower, associate, supporter," early 15c., from Old French adherent or directly from Latin adhaerentem (see adherent, adj.). Meaning "adhesive substance" is from 1912.