Short for them, especially in informal use. let 'em know who’s boss
More example sentences
- The others all put on good show so if you like 'em you'll probably see 'em.
- Plenty of American films get made without a single British villain in 'em.
- Allowing for time difference James is about to hit the Broadway stage now so all I can say is knock 'em dead James!
Middle English: originally a form of hem, dative and accusative third person plural pronoun in Middle English; now regarded as an abbreviation of them.
Definition of 'em in:
- The British & World English dictionary