Ur mom is a offensive saying that is common with 9 or 10 year olds.
Bob:How are you today?
Dan:How is your mom today?
Dan was found in a ditch 1 year later.
when you're not funny, so you say "ur mom" because you're probably a depressed bitch with no life.
Chad is so not funny. he keeps saying "ur mom". typical Chad.
a large type of cow that is very pretty and enjoys being milked
person one "my favorite cow is ur mom"
ur mom is a word alot of kids use to make fun of other kids ones that dont have a mom it is a fun word to use for kids that dont have a mom
i did ur mom last night
other kid : i dont have one
i know