Elementary Charge - Quantization

Quantization

Charge quantization is the principle that the charge of any object is an integer multiple of the elementary charge e. Thus, e.g., an object's charge can be exactly 0 e, or exactly 1 e, −1 e, 2 e, etc., but not, say, 1⁄₂ e, or −3.8 e, etc. (There may be exceptions to this statement, depending on how "object" is defined; see below.)

This is the reason for the terminology "elementary charge": it is meant to imply that it is an indivisible unit of charge.