n. A hormone (C8H11NO3) secreted by the adrenal medulla; it also serves as a neurotransmitter, released at synapses; called also noradrenaline. Chemically it is 2-amino-1-(3, 4-dihydroxyphenyl)ethanol. It is a precursor of epinephrine in the body. Syn. -- noradrenaline. [ WordNet 1.5 ]