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before vowels ap-, word-forming element meaning "from, away from, separate, free from," from Greek apo "from, away from; after; in descent from," in compounds, "from, asunder, away, off; finishing, completing; ceasing from; back again," from PIE root *apo- "off, away" (cf. Sanskrit apa "away from," Avestan apa "away from," Latin ab "away from, from," Gothic af, Old English of "away from").
apo- or ap-
Away from; off: aponeurosis.
Without; lacking; not: apoferritin.
Related to; derived from: apomorphine.