Counter Ult
Using your own ultimate to directly nullify or cancel an enemy ultimate.
Winning on ult-versus-ult matchups — canceling or riding out an offensive ult like Blade/Dragon/Grav with Trance or Beat. The cost is your own ult (the crux being that you pay an ult, unlike Ult Negate, which weathers it with a defensive CD such as Suzu or Lamp). Since the principle is to answer on reaction, it ties directly to "can you wait until they commit first (= can you hold it)", and it's the most efficient form of ult trade there is. Lose the mind game and get baited into throwing yours first and it's a huge loss instead.
Matching it only after confirming the enemy has committed a high-value ult (Blade/Dragon/Grav). Riding out Blade/Grav with Beat.
Committing your own ult first and having it ridden out by theirs, a dry ult. Spending the counter ult, then having no answer when the enemy follows with a different one.
Bait Ult
Forcing the enemy to spend an ultimate on empty space or a low-value target.
Resource Trade
Spending a minor cooldown to force a major defensive one, netting an advantage for the real fight.
Ult Cycle
Long-game management of team ult economy across fights — engineering favorable trades every round.
Ult Negate
Using a defensive ability (not an ult) to absorb an enemy ultimate, making it score zero kills.
Defensive Ult
An ultimate used to save teammates and reset a losing fight rather than to secure kills — Transcendence, Sound Barrier, Tree of Life, and similar.