Flannel Plaid Pajama Pants

flannel
Men's trousers made of such material
(usually in the plural) trousers made of flannel or gabardine or tweed or white cloth
A kind of soft-woven fabric, typically made of wool or cotton and slightly milled and raised
washcloth: bath linen consisting of a piece of cloth used to wash the face and body
a soft light woolen fabric; used for clothing
A washcloth

pajama
(usually plural) loose-fitting nightclothes worn for sleeping or lounging; have a jacket top and trousers
a pair of loose trousers tied by a drawstring around the waist; worn by men and women in some Asian countries
Pajamas, also spelled pyjamas (see also spelling differences) can refer to several related types of clothing. The original paijama are loose, lightweight trousers fitted with drawstring waistbands and worn in South and West Asia by both sexes.

plaid
Checkered or tartan twilled cloth, typically made of wool
A long piece of plaid worn over the shoulder as part of Scottish Highland dress
Any cloth with a tartan pattern
tartan: a cloth having a crisscross design
Plaid is the second studio album by guitarist Blues Saraceno, released in 1992 on Guitar Recordings.
Plaid is a London-based British electronic music duo comprising Andy Turner and Ed Handley. They are former members of The Black Dog and used many other names, such as Atypic (Andrew Turner) and Balil (Ed Handley), before settling on Plaid.

pants
bloomers: underpants worn by women; "she was afraid that her bloomers might have been showing"
Underpants
Trousers
Rubbish; nonsense
(pant) the noise made by a short puff of steam (as from an engine)
(pant) breathe noisily, as when one is exhausted; "The runners reached the finish line, panting heavily"