n.pl. (US pajamas) 1 a suit of loose trousers and jacket for sleeping in. 2 loose trousers tied round the waist, worn by both sexes in some Asian countries. 3 (pyjama) (attrib.) designating parts of a suit of pyjamas (pyjama jacket; pyjama trousers).
[ Urdu pa(e)jama f. Pers. pae, pay leg + Hindi jama clothing ]