swinging third strike

[Paul L]

OBR 2.00:
A CATCH is the act of a fielder in getting secure possession in his hand or glove of
a ball in flight and firmly holding it; providing he does not use his cap, protector, pocket or
any other part of his uniform in getting possession.

Sounds like once the ball is no longer in flight or if you use your uniform to gain secure possession, like it's lodged between your pants and your shirt, it is not a catch.

I always thought it was getting secure possession before touching the ground.