Definition of retro- in English:

retro-

combining form

  • 1Denoting action that is directed backwards or is reciprocal.

    ‘retrocede’
    ‘retroject’
  • 2Denoting location behind.

    ‘retrosternal’
    ‘retrochoir’

Origin

From Latin retro ‘backwards’.

Pronunciation

retro-

/ˈrɛtrəʊ/