burstburstburstsbursting2nounsomething that happens suddenly and quickly: a burst of laughterburstburstburstsbursting1verb (bursts, bursting, burst, has burst)1to break open suddenly or to make something do this: The bag was so full that it burst. He burst the balloon.2to go or come suddenly: Steve burst into the room.burst into somethingto start doing something suddenly: She read the letter and burst into tears (= started to cry). The car burst into flames (= started to burn).burst out laughingto suddenly start to laugh: When she saw my hat, she burst out laughing.