quantum

A quantum is the smallest amount of a physical quantity that can exist independently.

Example: Energy is transferred in small packets called quanta.

Quantum physics/computing/mechanics, etc. is related to quanta in sense 1.

Example: Particles like electrons behave differently at the quantum level.

A quantum change is a very large one.

Example: There has been a quantum shift in the way people think about this.

A quantum change is one that is sudden and non-continuous, moving from one state another without any intermediate states.

Example: A quantum leap occurs abruptly, without gradual transition.

The quantum of something is its total amount.

Example: The court decided the quantum of damages to be paid.