Describes what happens when a person freaks out, cracks, loses control of themselves. Life - reality at large- becomes overwhelming. They just can't deal with it all. The person may act out, withdraw, become emotional, run, etc...
I got a message from someone asking me to explain the difference between a temper tantrum and a meltdown. She wanted to know if I used the term interchangeably, or if there was an actual difference. I didn't take it as an insult, but as a way to teach the difference in my world. Truthfully, anyone who has a child on the spectrum completely understands this definition better than any dictionary could try to define it. A meltdown isn't referring to a child throwing a temper tantrum. I'd pay for a tantrum. A meltdown is an epic event when my sweet girl cannot handle the overwhelming sensory overload that is assaulting her. It usually lasts for hours and sometimes involves crisis intervention or a hospital visit. It is an event that I would never wish upon anyone.