Wiktionary
nitrilotriacetic acid
n. (context organic chemistry English) A polyamino carboxylic acid used as a chelate agent.
Wikipedia
Nitrilotriacetic acid
Nitrilotriacetic acid (NTA) is the aminopolycarboxylic acid with the formula N(CHCOH). It is a colourless solid that is used as a chelating agent, which forms coordination compounds with metal ions (chelates) such as Ca, Cu, and Fe.