trisodium orthophosphate tri·so·diu·morthophosphate uncommon noun 1. the tertiary phosphate of sodium used as a builder in soaps and detergents Synonymstrisodium phosphatetrisodium orthophosphatetribasic sodium phosphate Related words Broader terms builder WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
