See Also: vapour(1)(dictionary)
vapour(2)(dictionary)
vapour(dictionary)
vapour trail(dictionary)
water vapour(dictionary)

vapour(1) (iou)



vapour noun. Also *vapor. LME.
[Old & mod. French vapeur, vapour or Latin vapor steam, heat: see -OUR.]
Matter in the form of a tenuous fluid, either as a gas or as a suspension of minute droplets, esp. as produced by the action of heat on moisture. LME.
U. Le Guin They could see each other's breath, faint vapour in the steadily growing moonlight.
A substance in the form of a gas or of a suspension of minute droplets; spec. a fluid that fills a space like a gas but, being below its critical temperature, can be liquefied by pressure alone. Also loosely (chiefly poet.), smoke; a smoky substance emitted from burning material. LME.
S. Rushdie He inhaled vapours from crushed boiled eucalyptus leaves.
b. A mist or damp cloud rising by natural causes from the ground or from some damp place. LME.
c. fig. Something insubstantial or worthless. LME.
In pl.
a. Medicine. The unhealthy exhalations supposed to be developed in the organs of the body (esp. the stomach). arch. LME.
b. A condition of ill health supposed to be caused by such exhalations, as depression, hypochondria, etc. (arch.). Now chiefly joc., (an attack of) nervousness, indignant rage, etc.; hysterics. Freq. with the, now esp. in a fit of the vapours. M17.
Times A four-letter word is surely not enough to give anyone..the vapours.
A fantastic idea; a foolish boast. Now rare. E17.
Comb.: vapour barrier a thin layer of material, often polythene sheeting, impermeable to water vapour and used to insulate buildings, waterproof clothing, etc.; vapour-bath = steam bath s.v. STEAM noun; vapour density the density of a gas or vapour relative to that of hydrogen at the same pressure and temperature; vapour lock an interruption in the flow of a liquid through a pipe (esp. a fuel line) as a result of its vaporization; vapour pressure the pressure exerted by a vapour in contact with its liquid or solid form; vapour-proof adjective impervious to vapour; vapour tension = vapour pressure above; vapour trail a trail of condensed water vapour in the wake of an aircraft or rocket at high altitude, seen as a white streak against the sky (also called condensation trail); vapourware slang computer software that as yet exists only in the plans or publicity material of its developers.
vapourless adjective free from vapour; esp. (of wind or the sky) dry, cloudless: M19.