nutation noun. [nju:'teɪʃ(ǝ)n] E17.
[Latin nutatio(n-), formed as NUTATE: see -ATION.]
1. The action or an act of nodding the head. E17.

2. a. Chiefly Astronomy. An oscillation of the axis of a spinning body. Now usu. spec., a variation in the inclination of an axis from the vertical, esp. that which makes the precession of the earth's poles follow a wavy rather than a circular path. E18.
b. Rotation of an axis (of a beam, aerial, etc.) so as to describe a cone. M20.

3. Botany. The bending of a growing plant, esp. alternately in opposite directions, due to variation in growth-rate on different sides. Cf. CIRCUMNUTATION. L18.

■ nutational adjective L19.

[TahlilGaran] English Dictionary ▲