Long Underwear Pajamas

long underwear
Type of long (ankle length), fitted drawers, usually in a heavier-knit cotton or cotton blend, often with a waffled texture. Also referred to as long johns because they were first worn by John L. Sullivan as a boxing outfit in public.
Long underwear, often called long johns, is a style of two-piece underwear with long legs and long sleeves that is normally worn during cold weather. It offers an advantage over the union suit in that the wearer can choose to wear either the top, bottom, or both parts depending on the weather.
an undergarment with shirt and drawers in one piece

pajamas
(pajama) 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.
A suit of loose pants and jacket or shirt for sleeping in
A pair of loose pants tied by a drawstring around the waist, worn by both sexes in some Asian countries
(pajama) (usually plural) loose-fitting nightclothes worn for sleeping or lounging; have a jacket top and trousers