I don't like tangent...tangent is a line that intersects an arc at only one point.
I like tangent as explaining to people why if you round your throw the disc will pop out whenever your arm moves too fast. Like this link that BJ posted earlier, I don't know if I can multiquote across pages but this one:
https://v.redd.it/3y73w74fvnm11
It reminds me of a little high school physics demo my teacher, who was an ex-NHL enforcer for a few games and an awesome dude, showed us. Basically if you have a weight on a string and spin it around beside you as a vertical circle, the point of the most force on the string as at the bottom of the arc, when you have the constant acceleration from spinning the object + gravity's constant acceleration summing. The string will break at this point, and the object will shoot out tangent to the circle, which is directly forwards.
So that's why I show people to "pull straight" as the newbie simplification, and then the snap happens at the end so the disc doesn't get accelerated until that point and comes out tangent to the snap, which in those simple cases is forward at the target.
I'll think about it a bit too for what term/discussion to use.