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definitions

they're

[th air; unstressed th er]
  1. contraction of they are.
Can be confusedtheir there they're

Usage note

See contraction.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for they're

they're

contraction of
  1. they are
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012