Mini Sirloin 

(adj) referring to anything small. This reference usually occurs while hanging out with a group of people for an extended amount of time. Given enough time, someone in the group will probably sing the phrase "mini sirloin burgers" from the Jack in the Box commercial with the midgets and the infectious jingle. Subsequently it gets stuck in everyone's head and references to anything small become "mini sirloin"

petite girl: I can't hold all of these bags things at once!

big guy: Well hand them to me, I'm surprised you can hold on to anything with those mini sirloin hands.

Mini Sirloin by Changus Kahn July 11, 2009

Mini Sirloin Burger 

A type of order in the fast food restaurant Jack-in-the-box. It is composed of beef, with cheese on top, already put on ketchup. The burgers itself is $4.50, the combo is 1 dollar more. They give you 3 mini sirloin burgers. Each one is about 4 or 5 inches in height.

Hey, wanna go get some mini sirloin burgers at Jack in the box for $4.50?

Mini Sirloin Burger by n00bzers April 18, 2009