Merriam-Webster Collegiate Dictionary - chelate

 I. adjective  Date: 1826  1. resembling or having chelae  2. from the pincerlike way in which the metal ion is held of, relating to, or being a ~  II. verb  (~d; chelating)  Date: 1922  transitive verb to combine with (a metal) so as to form a ~ ring  intransitive verb to react so as to form a ~ ring  • chelatable adjective  III. noun  Date: 1943 a compound having a ring structure that usually contains a metal ion held by coordinate bonds