Meltdowns?

Hi everyone :) 

I have a question to ask and you might think it is silly.

I understand and can identify with 90% of what is posted on this forum but something keeps tripping me up. I don't **really know** what people mean when they say they had a 'meltdown'. 

I can only assume that I do not get these? I am on a lot of medication that makes it hard to really feel any feelings, so maybe I am just too numb to experience this.

Anyway, if anyone can share their experience of what happens/means when someone talks about meltdowns that would be helpful. 

(Is it the same as if, for example, you said a child was having a meltdown? eg. throwing a tantrum)

Thanks in advance and sorry if this is a stupid/obvious question.