"Pajama bottoms" refers to the pants or trousers that are specifically designed to be worn as part of a pajama set when you go to sleep or lounge around at home. Full definition
I'd style them with a black tulle skirt for daytime and a pair of pajama bottoms for evening. (withwonderandwhimsy.com)
Disana Merino Wool Leggings are pants or a light diaper cover, or use as pajama bottoms over your nighttime diapering setup. (greenmountaindiapers.com)
The vest breaks up the whole front without adding too much warmth and the leggings are just the most acceptable way to wear pajama bottoms in public! (whenthegirlsrule.com)