"haat" means: A periodic open-air market held on fixed days of the week, a fundamental institution of rural economic life across India, Bangladesh, and Ne.... This is a fairly neutral word with no inherent risk attached. There is no real cause for parental concern; it is descriptive vocabulary rather than something dangerous. If your child uses it, context will usually make the meaning clear. A brief, curious question about where they heard it is generally enough to know whether to follow up.