Definition of gill arch in US English:

gill arch

noun

  • 1Any of a series of bony or cartilaginous curved bars along the pharynx, supporting the gills of fish and amphibians.

    • ‘Originally, it may have been the main upper element of a gill arch.’
    • ‘Inside the fleshy gill arches, used for breathing, lies a system of bony gill arches, which form a finely divided sieve.’
    • ‘The fifth pair of gill arches is just in front of the pectoral fins.’
    • ‘The buccal cavity is lined with by gill arches, which bear numerous tooth patches.’
    • ‘It is not extant, but it had gill arches, fins, and several other characters indicative of an aquatic lifestyle.’
    1. 1.1 Any of the corresponding rudimentary structures in the embryos of higher vertebrates.
      • ‘This embryonic origin of the gill arches has been thought to be a good argument for their involvement with the jaw, but against their relationship with the limbs.’
      • ‘Primitively, then, there was a one-to-one correspondence between aortic arches and gill arches.’
      • ‘They differ from the earlier vertebrates in that some of the gill arches undergo modification in early development to become the jaw and its supporting structures.’