A turkey is either of two extant species of large birds in the genus Meleagris native to North America. Turkeys are classed in the order Galliformes. Within this family they are placed on one branch with Tetraonidae. Turkeys have a distinctive fleshy wattle that hangs from the underside of the beak, and a fleshy protuberance that hangs from the top of its beak called a snood. As with many galliform species, the female (the hen) is smaller than the male (the tom or gobbler), and much less colorful. With wingspans of 1.51.8 meters (almost 6 feet), the turkeys are by far the largest birds in the open forests in which they live, and are rarely mistaken for any other species.

Naming

When Europeans first encountered turkeys in the Americas they incorrectly identified the birds as a type of guineafowl (Numididae), also known as a turkey-cock from its importation to Central Europe through Turkey, and the name of that country stuck as the name of the bird. The confusion is also reflected in the scientific name: meleagris is Greek for guinea-fowl.

The names for M. gallopavo in other languages also frequently reflect its exotic origins, seen from an Old World viewpoint, and add to the confusion about where turkeys actually came from. The many references to India seen in common names go back to a combination of two factors: first, the genuine belief that the newly-discovered Americas were in fact a part of Asia, and second, the tendency during that time to attribute exotic animals and foods to a place that symbolized far-off, exotic lands. The latter is reflected in terms like "Muscovy Duck" (which is from South America, not Muscovy). This was a major reason why the name "turkey-cock" stuck to Meleagris rather than to the guinea fowl (Numida meleagris): the Ottoman Empire represented the exotic East.

The name given to a group of Turkeys is a rafter, although they are sometimes incorrectly referred to as a gobble or flock.

Several other birds which are sometimes called "turkeys" are particularly closely related: the Australian brush-turkey is a megapode, and the bird sometimes known as the "Australian turkey" is in fact the Australian Bustard, a gruiform. The bird sometimes called a Water Turkey is actually an Anhinga (Anhinga rufa)

Fossil turkeys

Many turkeys have been described from fossils. The Meleagrididae are known from the Early Miocene (c. 23 mya) onwards, with the extinct genera Rhegminornis (Early Miocene of Bell, U.S.) and Proagriocharis (Kimball Late Miocene/Early Pliocene of Lime Creek, U.S.). The former is probably a basal turkey, the other a more contemporary bird not very similar to known turkeys; both were much smaller birds. A turkey fossil not assignable to genus but similar to Meleagris is known from the Late Miocene of Westmoreland County, Virginia.