Etymonline has this entry for dibs:
Children's word to express a claim on something, 1932, originally U.S., apparently a contraction of dibstone "a knucklebone or jack in a children's game" (1690s), which is of unknown origin.
However, while Merriam-Webster's entry for dibs gives the same definition and origin as an abbreviation of dibstone, it traces the first known use to 1812.
An Ngram of dibs shows that it was indeed used in the early 1800s, having peaks in the 1840s and 1880s. After the 1880s peak, it drops gradually and does not really rise again until the 1980s. In fact, 1932 seems to be during one of the word's lowest points.
Given this information, why does Etymonline trace its origin to this low point in 1932 when it was actually in use over a century earlier? I'm looking for an explanation for the disparity between these sources. As far as I can determine, there is not another meaning of dibs to explain its earlier appearances.
Best Answer
According to World Wide Words, its usage appears earlier than 1932. But the usage in the first part of the 19th century may refer to a different meaning.