hearing-ear dog

[heer-ing-eer]
noun
  1. a dog that has been trained to alert a hearing-impaired person to sounds, as a telephone ringing or dangerous noises.

Origin of hearing-ear dog

First recorded in 1975–80; on the model of Seeing Eye dog
Also called hearing dog.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018