From Longman Dictionary of Contemporary Englishburst out phrasal verb1 burst out laughing/crying/singing etcSTART DOING something to suddenly start to laugh, cry etc Everyone burst out laughing.2 SAY/STATEto suddenly say something in a forceful way ‘I don’t believe it!’ she burst out angrily. → outburst(1) → burst→ See Verb table
Examples from the Corpus
burst out laughing/crying/singing etc• At that point I burst out laughing.• Charles didn't respond and after a frozen pause, she collapsed into a chair and burst out crying.• He did it so cleverly that you would think it was the real thing - until he burst out laughing.• I said and burst out crying.• Julie, surprised, burst out laughing.• The whole group bursts out laughing.• The woman and children burst out laughing again, getting up from the table and crowding round me.• I came down the steps of the Ashbery that morning and burst out laughing at the heat. 