c. 1600, "a living creature, one who breathes," agent noun from breathe. The meaning "spell of exercise to stimulate breathing" is from 1836; that of "a rest to recover breath" is from 1882.
Entries linking to breather
breathe v.
"to draw air into and expel it from the lungs; to inhale and exhale (a scent, etc.)," c. 1200, not in Old English, but it retains the original Old English vowel of its source word, breath. To breathe (one's) last "die" is from 1590s. To breathe down the back of (someone's) neck "be close behind" is by 1946. Related: Breathed; breathing.