Definition of tetra- in US English:

tetra-

(also tetr-)

combining form

  • 1Four; having four.

    ‘tetramerous’
    ‘tetragram’
    ‘tetrode’
  • 2Chemistry
    (in names of compounds) containing four atoms or groups of a specified kind.

    ‘tetracycline’

Origin

From Greek, from tettares ‘four’.