Axis – a line
Rotation – spin
The axis of rotation is the line (properly called
the axis) about which something rotates.
Some examples may help:
(a) if you
have a bicycle the axis of rotation of the wheel is the axle of your bike
(b) the axis of
rotation of the Earth is a line joining the North and South geographic poles
(c) the axis of
rotation of a diver is a line about which their body is rotating (spinning) as they dive
(d)
the axis of rotation of a record on a record deck or a CD on a CD player is the line about
which the record or CD is spinning
(e) the axis of rotation of a top is the line about which
the top is spinning
(f) the axis of rotation of a pendulum is a line through the point about
which the pendulum is swinging. You see the object does not have to rotate through the full
circle, it can swing back as in the movement of a pendulum.