D defs.my
Entry 2 senses Webster, 1913

Tetra-

· Tet·ra- · IPA /ˈtɛtɹə/
01 A combining form or prefix signifying four, as in tetrabasic, tetrapetalous.
  1. 1.
    A combining form or prefix signifying four, as in tetrabasic, tetrapetalous.
  2. 2.
    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.(Chem.)