Kiloran_speaking  has given the best term most people would refer to the loop or a loose thread on clothing as a snagged loop or snagged tread, however to allow for those that use the alternative term.

I am offering "pull" or "pulled loop" or pulled thread as [used here](https://www.instructables.com/id/How-to-Fix-a-Snagged-Sweater/)

"a snag is just a pulled loop in the knitted pattern"