fork-tailed petrel \ˈ ̷ ̷ˌ ̷ ̷-\noun alsoforked-tailed petrel\ˈ ̷ ̷ˌ ̷ ̷-\ : a bluish gray white-marked petrel (Oceanodroma furcata) that has a deeply forked tail and is widely distributed in the northern Pacific; also: any of several closely related birds with more or less forked tails