arcus zygomaticus vs zygomatic arch

arcus zygomaticus and zygomatic arch both are nouns.

Word	Noun	Adjective	Verb	Adverb
arcus zygomaticus	Yes	No	No	No
zygomatic arch	Yes	No	No	No

As nouns, arcus zygomaticus and zygomatic arch are synonyms defined as:

arcus zygomaticus and zygomatic arch: the slender arch formed by the temporal process of the cheekbone that bridges to the zygomatic process of the temporal bone

Other synonyms of arcus zygomaticus include zygoma.

arcus zygomaticus (noun)	zygomatic arch (noun)
the slender arch formed by the temporal process of the cheekbone that bridges to the zygomatic process of the temporal bone	the slender arch formed by the temporal process of the cheekbone that bridges to the zygomatic process of the temporal bone