RM stands for repetition maximum. For example, a 1RM for the squat would consist of the maximum amount of weight that one could squat for 1 rep (repetition).

A 5RM squat would be the maximum amount of weight one could squat for 5 reps.

pulse repetition frequency

One example could be - Mary wants a new job, the repetition of this one bores her.

Another example could be - The constant repetition is annoying.

An another might be - There is so much repetition in the book that it is too predictable.

In terms of exercise, a repetition is one complete movement of an exercise. For example, one push-up or one bicep curl. In terms of language, repetition is the act of repeating something that has already been said or written.