preexchange noun 2adjective 1verb 1forms 3 noun2 •An exchange that takes place beforehand.Both chiral derivatives can be produced by making use of preexchange of the β positions of 2-oxoglutarate in ²H₂O. — 1989 •An interaction that introduces and leads to but is not yet a true exchange. adjective1 •Occurring before an exchange.Reconsider preexchange financing strategy for alternative outcomes that may be more favorable to the parties. — 1980 verb1 •To exchange beforehand.The zeolite may be preexchanged to the desired metal form and calcined to lock the exchangeable, metal ions into position before compositing with the other ingredients. — 1981 formspreexchanged · preexchanging · preexchanges