Referring to the branchiae.
To or resembling gills of a fish or a homologous structure in higher animals.
The term originates from the Greek word for gills. In its early development, the human embryo resembles a tadpole, complete with markings that would theoretically develop into gills. Various body parts and organs eventually evolve from these specific areas in the embryo. If a leftover trace of this initial gill-like formation persists in the neck and forms a cyst, it is referred to as a branchial cyst to indicate its origin.