Question

What is meant by 'Quantization of charge'?

Answer 1

Quantization of charge implies that charge can assume only certain discrete values. That is to say the observed value of electric charge (q) of a particle will be integral multiples of (e) $1.6\times {10}^{-19}$ coulombs.
i.e.
$q=ne$ where $n=0,1,2,....$ (both positive and negative integers)
The charge cannot assume any value between the integers.