demersal adjective 2noun 1forms 3 adjective2 •That lives near the bottom of a body of water.The young tend to occupy a pelagic habitat, but shift to a more demersal lifestyle with maturity. — 2003 •Taking place near the bottom of a body of water. noun1 •Any demersal organism, especially a groundfish. formsdemersals · more demersal · most demersal