Blade

From Ultipedia

A throw that either flies or lands vertically. Blades (Also known as a Knife in the UK) are fast and notoriously difficult to catch.

Blades are sometimes used on a throw-off or pull to obtain a roll in order to move the disc up further. They are most commonly used to put the disc over the top of a wall of players thereby making it more difficult for the defence to intercept, this is most commonly used indoors where there is no wind to interfere with the discs intended destination.

A Blade is thrown similar to that of a sidearm, but at a 90 degree (vertical) angle.