'Expiratory' definitions:

Definition of 'expiratory'

(from WordNet)
adjective
Of or relating to the breathing out phase of respiration

Definition of 'Expiratory'

From: GCIDE
  • Expiratory \Ex*pir"a*to*ry\, a. (Physiol.) Pertaining to, or employed in, the expiration or emission of air from the lungs; as, the expiratory muscles. [1913 Webster]