pyjamas
(BrE) (AmE pajamas) noun [pl.]

1 a loose jacket and trousers/pants worn in bed:
a pair of pyjamas

2 loose trousers/pants tied around the waist, worn by Muslims of both sexes in some Asian countries

pyjama (BrE) (AmE pajama) adjective [only before noun]:
pyjama bottoms

IDIOMS see CAT