Tet"ra- (?). [Gr. , from , , four. See Four.]
A combining form or prefix signifying four, as in tetrabasic, tetrapetalous.
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.
© Webster 1913.