\Nu*ta"tion\, n. [L. nutatio a nodding, fr. nutare to
nod: cf. F. nutation.]
1. The act of nodding.
         So from the midmost the nutation spreads, Round and
         more round, o'er all the sea of heads. --Pope.
2. (Astron.) A very small libratory motion of the earth's
   axis, by which its inclination to the plane of the
   ecliptic is constantly varying by a small amount.
3. (Bot.)
   (a) The motion of a flower in following the apparent
       movement of the sun, from the east in the morning to
       the west in the evening.
   (b) Circumnutation.