anvil vs incus

anvil and incus both are nouns.

Word	Noun	Adjective	Verb	Adverb
anvil	Yes	No	No	No
incus	Yes	No	No	No

As nouns, anvil and incus are synonyms defined as:

anvil and incus: a small bone in the middle ear between the malleus and the stapes

anvil (noun)	incus (noun)
a heavy block of iron or steel on which hot metals are shaped by hammering	a small bone in the middle ear between the malleus and the stapes
a small bone in the middle ear between the malleus and the stapes