first dibs on something

first dibs on something

or

dibs on something

INFORMAL
If you have first dibs on something or dibs on something, you have claimed the right to have it or use it before anyone else. The main reason my best friend Sue and I wanted to join was so that we could have first dibs on an endless supply of mouthwatering cakes. Ralph's brother now has dibs on the job of horse trainer. Note: This expression comes from an old children's game in which the pieces were called dib stones.
See also: dibs, first, on, something