A sirloin is a piece of meat from the upper part of a cow's back leg.
Sirloin is a tasty and special kind of meat that people often eat at fancy dinners or cookouts.
Examples:
I want to eat a big piece of sirloin.
We are having sirloin for dinner tonight.
The sirloin is very tasty.
The sirloin is too big for my plate!
I ate a whole sirloin by myself!
The sirloin was the best part of the meal.