tet·ra·eth·yl lead also tet·ra·eth·yl·lead 
(tĕt′rə-ĕthəl-lĕd′)
(tĕt′rə-ĕthəl-lĕd′)n.
A colorless, poisonous, oily liquid, C8H20Pb, comprised of four ethyl groups on each lead atom, used in gasoline for internal-combustion engines as an antiknock agent.