One who or that which has corresponding functions or characteristics.
Either of two parts that fit together, or complement one another.
One who or that which resembles another.
A duplicate of a legal document.
Either half of a flattened fossil when the rock has split along the plane of the fossil.
To counterbalance.
One who or that which helps something to happen.
One who encourages a bad habit in another (typically drug addiction) by their behaviour.
One who gives someone else the power to behave in a certain way.