WordWeb Online

1. A state of depression
   "he had a bad case of the vapours"; "he had a bad case of the vapours"
   - blues, blue devils, megrims, vapors [US]

1. A visible suspension in the air of particles of some substance
   - vapor [US]
    
2. The process of becoming a vapour
   - vaporization, vaporisation [Brit], vapor [US], evaporation

Type of: depression, phase change, phase transition, physical change, state change, suspension

Encyclopedia: Vapour