edible fruit of an endogenous plant of the tropics, 1590s; in reference to the plant itself, 1690s; borrowed by Spanish or Portuguese from a West African word, possibly Wolof banana. The plant seems to be native to Southeast Asia and the East Indies; it was introduced in Africa in prehistoric times and brought to the New World from Africa in 1516.
Banana-skin is from 1851, banana-peel from 1874, both originally with reference to them being left carelessly on the ground and liable to cause a pratfall when trodden upon. The nuisance was a frequent complaint in cities, and there seems to have been a regular insurance scam targeting streetcar lines in the 1890s.
The companies that have paid damages for fraudulent claims are the Manhattan Elevated Company, New York; West End Street Railway, Boston; Chicago City Railway Company, Chicago; Illinois Central Railroad Company, Chicago. The alleged injury was the same in each case, paralysis of the lower limbs, caused by slipping on a banana peel. [Street Railway Review, Jan. 15, 1895]
Banana split is attested from 1905. Banana oil "nonsense" is slang from c. 1910; probably from earlier use as the name of a chemical substance (also called banana liquid and essence of banana) used by 1873, one of the earliest artificial flavorings. Top banana, second banana, etc. are 1950s, from show business slang use of banana for "comedian," especially in a burlesque show.