ha, hah /hɑː/ interjection SURPRISEDused when you are surprised or have discovered something interesting 哈〔表示惊奇或发现了有趣的事物〕 Ha! I thought it might be you hiding there! 哈!我想可能就是你藏在那里!
ha• Ha! I told you it wouldn't work.
From Longman Business Dictionary
haha written abbreviation for HECTARE