rotator

n. [ L. ] 1. (Anat.) that which gives a rotary or rolling motion, as a muscle which partially rotates or turns some part on its axis. [ 1913 Webster ]

2. (Metal.) A revolving reverberatory furnace. [ 1913 Webster ]

a. [ Cf. F. rotatoire. See Rotate, Rotary. ] 1. Turning as on an axis; rotary. [ 1913 Webster ]

2. Going in a circle; following in rotation or succession; as, rotatory assembles. Burke. [ 1913 Webster ]

3. (Opt.) Producing rotation of the plane of polarization; as, the rotatory power of bodies on light. See the Note under polarization. Nichol. [ 1913 Webster ]