Middle English; since 17c. taken as a colloquial abbreviation of them, but originally at least in part a form of hem, dative and accusative of the third person plural pronoun.
Entries linking to 'em
them pron.
third person plural pronoun, c. 1200, from Old Norse þeim, dative of plural personal and demonstrative pronoun þeir (see they). Replaced Old English cognate him, heom.