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.
One who helps; an aide; assistant; auxiliary.
That which helps; anything serving to assist.
A locomotive that assists a train, usually on steep gradients.
A person who does cleaning and cooking in a family home, or in a market; domestic employee.