I have read about Rotatory Motion it says

"It is that motion in hwich body, which is not a point mass body is moving such that all its constituent particles move simultaneously along concentric circles, whose centres lie on a line, called axis of rotation and shift through equal angle in a given time".

My question..

Q1. what is the meaning of line "whose centres lie on a line, called axis of rotation and shift through equal angle in a given time". Explain it briefly and clearly. If possible with exampele.

The center of motion for each particle is located on the same line. That line is the axis of rotation. The angular rate of all particles is the same. (Angular rate=angular velocity).