MEH is like a verbal shoulder shrug. For those moments when you just don't care. Honey whats for diner? Meh, I'm not ready to eat. To the gamers, you know what Meh means.
If you're a science buff you might know Meh as: Multiple-effect humidification (MEH) is a method used for thermal desalination of sea water. It uses multiple evaporation-condensation cycles at separate temperature levels to minimize the total energy consumption of solar humidification processes.