The BB is the 1st bet.
The next raise (in your example the minraise to 200) is the 2nd bet
A following raise (any size, in your example 300 is a minraise) is the 3rd bet.
So a raise after the 2nd bet is called a 3-bet, it matters not what the actual amounts/sizes of these raises are as long as they are legal raises.
For example, in a $0.50/$1.00 cash game
SB puts out $0.50
BB puts out $1.00
UTG raises $9 to $10 total
CO calls $10
BTN raises $90 to $100 total
The BTN has made a 3-bet of UTG's raise (2nd bet).