What is the difinition of a chemtrail?

I like this thread and where it went a lot of good info. That being said I tend to believe in the Geo-Enginering aspect. If your nation was full of drought and you thought it was possible to change with the help of a few "friends' and all is hunky dory again, why not..... But as far as HARSH NASTY KILLING CHEMICALS to depopulate the country im not buying it, but nothing would suprise me in this fascist country anything goes, whenever it needs too. Long live the Roman Empire