Aren't Definition

ärnt, ärənt
contraction
Are not.
Webster's New World
Am not.
I'm helping you, aren't I?
Webster's New World

Contraction of are not.

Wiktionary

(colloquial) Spelling replacement of the homonym an’t, a contraction of “am not”, used e.g. in the construction aren’t I?

Wiktionary

Origin of Aren't

  • are +‎ -n’t

    From Wiktionary