Two unrelated groups of birds converged on the same look: a medium-sized, slender songbird in bold yellow-orange and black that feeds high in leafy trees. European settlers in North America applied a familiar name to an unfamiliar bird, and the label stuck through subsequent taxonomy. The Baltimore oriole sits in Icteridae with grackles, cowbirds, meadowlarks and red-winged blackbirds; Old World orioles sit in Oriolidae.
The nest is the more distinctive trait. The female weaves a deep hanging pouch, typically around fifteen centimetres deep, from plant fibre, hair and increasingly synthetic twine, lashed to drooping outer twigs where climbing predators struggle to reach. Construction takes about a week, and the structure hangs on well after the leaves fall.
A long-running taxonomic wobble is worth flagging. Baltimore and Bullock's orioles hybridise on the Great Plains and were merged as a single species, the northern oriole, from the 1970s. Later work on the hybrid zone showed limited introgression, and they were split again in the 1990s.