It is called atari 当たり.
The word is connected to the verb ataru 当たる.
Which indeed can mean to hit, to meet, to collide, to touch, to clash.
Compare atemi 当て身.
You move the partner using "the point at which the ki collides". (see 0:40)
I see blending and redirection. I would have to feel it to see if it indeed collides. It may just be another use of the word. I see no clash.