term:

Co-

co- prefix

1 : with
: together
: joint
: jointly [codefendant]
2 a : associated in an action with another
: fellow [co-conspirator]
b : having a usually lesser share in duty or responsibility
: alternate
: deputy [co-counsel]

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.