An onomatopoeic interjection representing laughter (ha ha ha).
「冗談だよ」彼はハハハと笑った。
"I was joking," he said, laughing ha ha ha.
皆が面白がって、ハハハと笑い声が教室に響いた。
Everyone found it funny and ha ha ha laughter echoed through the classroom.
老人は昔話をして、ハハハと陽気に笑った。
The old man told an old story and laughed cheerfully, ha ha ha.