2. Prefix. without, or lacking ¹
3. Prefix. (chemistry) derived from, or related to ¹
¹ Source: wiktionary.com
Medical Definition of Apo-
1. Combining form meaning, usually, separated from or derived from. Origin: G. Apo, away from, off; apo-becomes ap-, especially before a vowel or h (05 Mar 2000)