Chapter Rosette to Rotche of R by Webster's Dictionary (1913 Edition)

1. The act of turning, as a wheel or a solid body on its axis, as distinguished from the progressive motion of a revolving round another body or a distant point; thus, the daily turning of the earth on its axis is a rotation; its annual motion round the sun is a revolution.

2. Any return or succesion in a series.

Moment of rotation. See Moment of inertia, under Moment. — Rotation in office, the practice of changing public officers at frequent intervals by discharges and substitutions. — Rotation of crops, the practices of cultivating an orderly succession of different crops on the same land.

Rotation
(Ro*ta"tion) a. Pertaining to, or resulting from, rotation; of the nature of, or characterized by, rotation; as, rotational velocity.

Rotative
(Ro"ta*tive) a. [Cf. F. rotatif.] turning, as a wheel; rotary; rotational.

This high rotative velocity of the sun must cause an equatorial rise of the solar atmosphere.

Siemens.

Rotative engine, a steam engine in which the reciprocating motion of the piston is transformed into a continuous rotary motion, as by means of a connecting rod, a working beam and crank, or an oscillating cylinder.

Rotator
(Ro*ta"tor) 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.

2. (Metal.) A revolving reverberatory furnace.

Rotatoria
(||Ro`ta*to"ri*a) n. pl. [NL.] (Zoöl.) Same as Rotifera.

Rotatory
(Ro"ta*to*ry) a. [Cf. F. rotatoire. See Rotate, Rotary.]

1. Turning as on an axis; rotary.

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

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

Rotatory
(Ro"ta*to*ry), n. (Zoöl.) A rotifer. [R.] Kirby.

Rotche
(Rotche) n. (Zoöl.) A very small arctic sea bird (Mergulus alle, or Alle alle) common on both coasts of the Atlantic in winter; — called also little auk, dovekie, rotch, rotchie, and sea dove.