Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
vapor, etc (US) = vapour, etc
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.
vapour [ˈveɪpər]
(US) vapor n (gas, mist, steam) пар# * is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.