Latin for "Your mom". Can be used to display one's superiority; even moreso than conventional "Your mom" usage it can, because it's in a different language and makes you sound smarter.
1: So, what're you doin' tonight?
2: Tuimater! O!
3: *face melts from display of awesomenity*
Pajama casual is a term used when working from home and preparing for a video conference. All business above the waist and your pajama pants down below.