Word: 
n.  1.  Quantity; amount.  
2.  (Math.) A definite portion of a manifoldness, limited by a mark or by a boundary.

Noun  1.  quantum  a discrete amount of something that is analogous to the quantum in quantum theory 
2.  quantum  (physics) the smallest discrete quantity of some physical property that a system can possess (according to quantum theory) 
quantum  time slice 