The griffin is a legendary creature with the body of a lion and the head and often wings of an eagle. As the lion was traditionally considered the king of the beasts and the eagle was the king of the birds, the griffin was thought to be an especially powerful and majestic creature. Griffins are normally known for guarding treasure. In antiquity it was a symbol of divine power and a guardian of the divine.

Most contemporary illustrations give the griffin legs like an eagle's legs with talons, although in some older illustrations it has a lion's forelimbs; it generally has a lion's hindquarters. Its eagle's head is conventionally given prominent ears; these are sometimes described as the lion's ears, but are often elongated (more like a horse's), and are sometimes feathered.

Infrequently, a griffin is portrayed without wings (or a wingless eagle-headed lion is identified as a griffin); in 15th-century and later heraldry such a beast may be called an alce or a keythong. In heraldry, a griffin always has forelegs like an eagle's hind legs; the beast with forelimbs like a lion's forelegs was distinguished by perhaps only one English herald of later heraldry as the opinicus; the word "opinicus" escaped the editors of the Oxford English Dictionary. The modern generalist calls it the lion-griffin, as for example, Robin Lane Fox, in Alexander the Great, 1973:31 and notes p. 506, who remarks a lion-griffin attacking a stag in a pebble mosaic at Pella, perhaps as an emblem of the kingdom of Macedon or a personal one of Alexander's successor Antipater.

After "griffin", the spelling gryphon is the most common variant in English, gaining popularity following the publication of Alice's Adventures in Wonderland as can be observed from usage in The Times and elsewhere. Less common variants include gryphen, griffen, and gryphin.; from Latin grȳphus, from Greek γρύψ gryps, from γρύπος grypos hooked. The spelling "griffon" (from Middle English and Middle French) was previously frequent but is now rare, probably to avoid confusion with the griffon dog breed.