late 14c., "act of exhalation; that which is exhaled," from Latin exhalationem (nominative exhalatio) "an exhalation, vapor," noun of action from past-participle stem of exhalare "to breathe out" (see exhale).
Old English bræð "odor, scent, stink, exhalation, vapor" (the Old English word for "air exhaled from the lungs" was æðm), from Proto-Germanic *bræthaz "smell, exhalation" (source also of Old High German bradam, German Brodem "breath, steam"), perhaps [Watkins] from a PIE root *gwhre- "to breathe; smell." The original long vowel (preserved in breathe) has become short.
The meaning "ability to breathe," hence "life" is from c. 1300. The meaning "a single act of breathing" is from late 15c.; the sense of "the duration of a breath, a moment, a short time" is from early 13c. The meaning "a breeze, a movement of free air" is from late 14c.
"bad breath," 1874, coined in Modern Latin from Latin halitus "breath, exhalation, steam, vapor" (which is related to halare "to breathe, emit vapor") + Greek-based noun suffix -osis.
early 15c., expiracioun, "vapor, breath," from Latin expirationem/exspirationem (nominative expiratio/exspiratio) "a breathing out, exhalation," noun of action from past-participle stem of expirare/exspirare "breathe out; breathe one's last" (see expire). Meaning "termination, end, close" is from 1560s.
late 14c., "vapor, odorous vapor; exhalation," from Old French fum "smoke, steam, vapor, breath, aroma, scent" (12c.), from Latin fumus "smoke, steam, fume, old flavor" (source also of Italian fumo, Spanish humo), from PIE root *dheu- (1) "dust, vapor, smoke."
In old medicine, an "exhalation" of the body that produces emotions, dreams, sloth, etc; later especially of smokes or vapors that go to the head and affect the senses with a narcotic or stifling quality.
1725, "a sound of or resembling or involving the letter 'H'," especially at the beginning of a word, from Latin aspirationem (nominative aspiratio) "a breathing, exhalation; the pronunciation of the letter H," from aspirare (see aspire).
late 14c., respiracioun, "act or process of breathing, inhalation and exhalation of air by the lungs," from Latin respirationem (nominative respiratio) "breathing, respiration," noun of action from past-participle stem of respirare "breathe again, breathe in and out," from re- "again" (see re-) + spirare "to breathe" (see spirit (n.)). Extended to plants by 1831. Milton used it for "act of returning to life" ("breathing again").
1620s, "of poisonous smell, foul, noxious," from Late Latin mephiticus, from Latin mephitis, mefitis "noxious vapor, a pestilential exhalation, especially from the earth" (also personified as a goddess believed to have the power to avert it), an Italic word of uncertain origin. English use of mephitis is attested from 1706.
late 14c., from Anglo-French vapour, Old French vapor "moisture, vapor" (13c., Modern French vapeur) and directly from Latin vaporem (nominative vapor) "a warm exhalation, steam, heat," which is of unknown origin. Vapors "fit of fainting, hysteria, etc." is 1660s, from medieval notion of "exhalations" from the stomach or other organs affecting the brain.
Proto-Indo-European root meaning "cloud."
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit nabhas- "vapor, cloud, mists, fog, sky;" Greek nephele, nephos "cloud;" Latin nebula "mist, vapor, fog, smoke, exhalation;" German Nebel "fog;" Old English nifol "dark, gloomy;" Welsh niwl "cloud, fog;" Slavic nebo.