Dibs
mid 18th century (denoting pebbles used in a children's game): from earlier dib-stones, perhaps from dib.
wiktionary
Since the early 19th century, of disputed origin. Most commonly thought to be from dibstones(“counters used in a game with the same name”). Also from dib(“to tap”) or related to northern English dip(“small depression in the ground”), or a shortened version of divide.
From Arabic دِبْس (dibs).
dibs
etymonline
dibs (interj.)
children's word to express a claim on something, 1915, originally U.S., apparently from earlier senses "a portion or share" and "money" (early 19c. colloquial), probably a contraction of dibstone "a knuckle-bone or jack in a children's game" (1690s), in which the first element is of unknown origin. The game consisted of tossing up small pebbles or the knuckle-bones of a sheep and catching them alternately with the palm and the back of the hand.