Rotation is circular movement. A rotation is the movement of something through one complete circle.
例句
...the daily rotation of the earth upon its axis.地球每天绕地轴自转
N-UNCOUNT
轮流;轮班
The rotation of a group of things or people is the fact of them taking turns to do a particular job or serve a particular purpose. If people do something in rotation, they take turns to do it.
例句
He grew a different crop on the same field five years in a row, what researchers call crop rotation...他连续5年在同一块地里种植不同的作物，研究人员称之为轮作。Once a month we met for the whole day, and in rotation each one led the group.我们每个月聚在一起一整天，轮流担任领队。