If the player making it was the last raiser pre-flop, it's a continuation bet. If the player making it called a raise pre-flop and is OOP, it's a donkbet or donk lead. If the player called in position and the PFR didn't c-bet, you can call it a stab, or a bet in position, or a 'bet vs missed CB'. On later streets, such bets are sometimes called 'probes'.
"2-bet" means the second bet-size on that street. e.g. pre-flop, it costs 1bb to limp in by matching the BB. A raise is the second bet size. A re-raise is a 3-bet. Post-flop, the same applies. The first bet is just a bet, a raise is a 2-bet, and a re-raise is a 3-bet.
