hyomandibular adjective 2noun 1forms 1 adjective2 •Relating to the hyomandibula. •Relating both to the hyoid arch and the mandible or lower jaw.the hyomandibular bone or cartilage, a segment of the hyoid arch which connects the lower jaw with the skull in fishes noun1 •The hyomandibular bone or cartilage. formshyomandibulars