Of or pertaining to the nucha or nape: as, the nuchal muscles.In entomology:Situated superiorly, just behind the head: said especially of ornaments, processes, etc., on an insect-larva.Of or pertaining to the metanotal nucha.In the trilobites, relating to the axial segment and groove at the base of the cephalon.n. One of two or more plates forming part of the covering of the dorsal portion of the neck in reptiles. The term is usually applied to the well-marked bony plates of crocodiles but also, as in lizards, to horny plates or shields.