Definition of apo- in US English:

apo-

prefix

  • 1Away from.

    ‘apocrypha’
    ‘apostrophe’
    1. 1.1 Separate.
      ‘apocarpous’
  • 2Astronomy
    Denoting the furthest point in the orbit of a body in relation to the primary.

    ‘apolune’
    Compare with peri-

Origin

From Greek apo ‘from, away, quite, un-’.