branchial arch vs gill bar

branchial arch and gill bar both are nouns.

Word	Noun	Adjective	Verb	Adverb
branchial arch	Yes	No	No	No
gill bar	Yes	No	No	No

As nouns, branchial arch and gill bar are synonyms defined as:

branchial arch and gill bar: one of the bony or cartilaginous arches on each side of the pharynx that support the gills of fishes and aquatic amphibians

Other synonyms of branchial arch include gill arch.

branchial arch (noun)	gill bar (noun)
one of the bony or cartilaginous arches on each side of the pharynx that support the gills of fishes and aquatic amphibians	one of the bony or cartilaginous arches on each side of the pharynx that support the gills of fishes and aquatic amphibians