Chelation describes the bonding of the organic ligand(s) to a metal atom, forming a metal complex. A compound that avidly engages in this kind of complex formation is often called a chelating agent (for example, EDTA).
The term chelate was first applied in 1920 by Sir Gilbert T. Morgan and H.D.K. Drew in J. Chem. Soc., 1920, 117, 1456, who stated: "The adjective chelate, derived from the great claw or chela (chely- Greek) of the lobster or other crustaceans, is suggested for the caliperlike groups which function as two associating units and fasten to the central atom so as to produce heterocyclic rings."