Sizing means how much you bet or your Villain bets-- NL allows us to choose any size but using different sizes on different boards allows us to maximize our wins.
Common sizing terms are Pot size betting the same amount as the pot -Over pot -half pot-min bet etc
The sizing we choose is based on our Goal. If we have the "nuts" best possible hand-- and we think our Villain will call we bet all-in--if we think they are weak and will only call a small bet we size down from all-in.

