To understand what it means, please provide more context:
* Where did you hear "kalo" used? (e.g., online chat, conversation, song lyrics)
* What was the overall topic of the conversation?
* What words were used around "kalo"?
For example, "kalo" might be a shortened form of "kalau" in Bahasa Indonesia, which means "if."
Once you provide more information, I can help you find the correct translation.