| ̷ ̷ ̷ ̷| ̷ ̷ ̷ ̷ ̷ ̷| ̷ ̷ ̷ ̷ ̷ ̷ noun
Etymology: tetraethyl + ammonium
: the quaternary ammonium ion (C 2 H 5 ) 4 N + , containing four ethyl groups ; also : a salt of this ion (as the deliquescent crystalline chloride used as a ganglionic blocking agent)