. Also, burst out. Give sudden utterance to. For example, burst into tears or laughter or song or speech or burst out crying or laughing or singing, etc. mean “begin suddenly to weep, laugh, sing,” and so on, as in When she saw him, she burst into tears, or I burst out laughing when I saw their outfits, or When they brought in the cake, we all burst into song. These terms have been so used since the late 1300s.