(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