Dragons are chimerical beasts, with two or four legs, with or without wings or horns, and skin covered with scales or hairs or feathers. Their tails come in endless varieties. Snakes or serpents or worms (wyverns)can also be dragons.
Edward Topsell summarized what was known about winged dragon by ancient and medieval writers in The History of Four-footed Beasts and Serpents (1658):
“There are some Dragons which have wings and no feet, some again have both feet and wings, and some neither feet nor wings, but are only distinguished from the common sort of Serpents by the comb growing upon their heads, and the beard under their cheeks. St. Augustine saith that Dragons abide in deep Caves and hollow places of the earth, and that sometimes when they perceive moisture in the air, they come out of their holes & beating the air with their wings, as it were the strokes of oars, they forsake the earth and fly aloft. Their wings are of a skinny substance, and very voluble, and spreading wide . . .”
To learn more about the history of dragons, see The Evil, Medieval Ancestors of Modern Dragons
13th-century English manuscript; Courtesy of the British Library Catalogue of Illuminated Manuscripts.