What does increments mean ?

The increment is the process which ensures an increase in the total amount by a specific rate. For example – one can get an annual salary increment of 10%. 

This can be a fixed pay increment designed to reward the employee's performance, not eligible for the base salary raise. This can be used when the proposed salary remains within the predetermined band or scale for the job assigned.

Mostly increments and appraisals are part of the same process where appraisal provides a detailed analysis of the strengths and weaknesses of the employee, and the individual’s appraisal can lead to a raise.