[¦naf·thə‚lēn·ə¦sēd·ik ′as·əd] (organic chemistry) C10H7CH2COOH White, odorless crystals, melting at 132-135°C; soluble in organic solvents, slightly soluble in water; used as an agricultural spray. Abbreviated NAA. Also known as 1-naphthylacetic acid.AcronymsSeeNAA