This is the name of the oldest monastic order in Western Christendom whose founder was Saint Benedict (about 480 - 547).
Saint Benedict was born in Umbria and visited Rome. He first established a monastery at Subiaco and then at Monte Cassino, where he set out the rules of his order - vows of poverty, chastity and obedience. These became the basis of many other monastic foundations.
Benedictine monks normally have a black habit, but occasionally wear white.
There was also a Benedictine order of nuns.