Definitions
1.NounEither of two parts that fit together, or complement one another."Those brass knobs and their hollow counterparts interlock perfectly."
2.NounA duplicate of a legal document.
3.NounOne who or that which resembles another. (Can we add an example for this sense?)
4.NounOne who or that which has corresponding functions or characteristics."Her French counterpart attended the meeting via video call.; The two companies are working together with their respective counterparts in Asia."
5.NounEither half of a flattened fossil when the rock has split along the plane of the fossil.
6.VerbTo counterbalance. (Can we add an example for this sense?)