phosphate UK /ˈfɒsfeɪt/US /ˈfɑsfeɪt/noun 4verb 1forms 3 noun4 •Any salt or ester of phosphoric acid.Make sure you don’t use detergents with phosphates or nonylphenol ethoxylate surfactants, but that information is rarely available on the labels. — 2009 •Any fertiliser containing phosphate compounds. •Guano (containing high levels of phosphates and harvested for the fertiliser industry). •(US, old-fashioned) A carbonated soft drink containing phosphoric acid, often flavored with a fruit-based syrup. verb1 •To treat or coat with a phosphate or phosphoric acid. formsphosphated · phosphating · phosphates