"Pajama pants" refers to a type of loose and comfortable trousers or bottoms that are typically worn for sleeping or lounging around at home. Full definition
I do have the drawers sorted by pajamas pants, shirts, long sleeves, short sleeves. (thestir.cafemom.com)
Nothing feels better than slipping into knit maternity pajama pants on a cold night. (shoppinkblush.com)
Every so often, as I was watching, I would flash back to this image of myself in pajama pants with really gross hair typing away on my computer, and then juxtapose it over the gorgeous shot of the Sears Tower or Navy Pier or the Abnegation sector on this big screen in front of me, and it was so ridiculously awesome and surreal I just wanted to laugh and cry all at once. (thehollywoodnews.com)