Tet″ra– (?). [Gr. τέτρα-, from τέσαρεσ, τέτταρεσ, four. See Four.] 1. A combining form or prefix signifying four, as in tetrabasic, tetrapetalous.
2. (Chem.) A combining form (also used adjectively) denoting four proportional or combining parts of the substance or ingredient denoted by the term to which it is prefixed, as in tetra-chloride, tetroxide.