What does rotation mean in medical terms?

In medical terms, as in lay language, rotation means turning around an axis. The common uses in medical/anatomical terms are to describe movement at a joint (for instance, rotation of the neck is the movement you use when you shake your head "no." External rotation at the shoulder is what you use when you scratch the back of your neck.) Also, rotation might describe a malposition of an organ -- for instance, a slightly twisted uterus rotated left might be called levorotated (and to the right, dextrorotated.)