tetra

Tetra- \Tet"ra-\ [Gr. te`tra-, from te`sares, te`ttares, four. See {Four}.] 1. A combining form or prefix signifying four, as in tetrabasic, tetrapetalous. [1913 Webster] 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. [1913 Webster]