pref.- Acting in the place of; substituting for: proform.
- Supporting; favoring: prorevolutionary.
[Middle English, from Old French, from Latin pro-, prō-, from prō, for.]
pro-2 pref.- Earlier; before; prior to: procambium.
- Rudimentary: pronucleus.
- Anterior; in front of: procephalic.
[Middle English, from Old French, from Greek, from pro, before, in front.]