nu·ta·tion /nuˈteʃən, nju-/
垂頭,下垂,俯下,章動
Nu·ta·tion n.
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.
◄ ►
nutation
n : uncontrolled nodding