It is remuneration. The word comes from the Latin remunerari, to reward or pay back, built on munus, a gift or a duty. The same munus is in munificent, which means very generous.
Many people say and even write renumeration, with the n and the m swapped. They are thinking of number and numerous, as if pay were about counting money. Those words come from a different Latin root, numerus, a number.
To remember the order, think of the m in money: remuneration is money for your work, and the m comes first. The verb is remunerate, rih-MYOO-nuh-rayt, with the stress on myoo.