The swing

Basic attack: the default swing a unit makes on its beat, scaled off its power. It strikes a random foe in the enemy front row, moving to the back row once the front row has fallen.
Special: a unit's signature skill, cast automatically the moment its energy reaches 1000, then energy resets to 0. Its energy bar and frame edge pulse once it reaches 1000, until the special fires.
Energy regen: how fast a unit's energy refills, per second, every beat. Each hero has their own rate.

Order and rows

Acting order: positions act in fixed order 1, 2 (front) then 3, 4, 5 (back), every round, on both sides. A position spends its beat even if it is empty or its unit has fallen.
Front / Back: the front pair act early each round with little energy banked, so they usually swing basics. The back three act later with more energy, so they often cast first.

Rolls

Crit: a lucky hit for extra damage. Crit chance and crit damage are per hero, read from the stats sheet (a plain hero sits near 16% for 150% damage) and raised by the Constellations, gear and relics.
Evade: the target slips the attack entirely and takes nothing. Each hero uses its own evade stat.
Block: the target catches the blow and takes only 55% of the damage.

Control

Hush: knocks a foe's energy back so its next action is a basic, not a special.
Stagger: the foe skips its next beat entirely; the beat itself is still spent.
Freeze (Cassandra) and Petrify (Perseus) are Stagger flavors that print their own odds.

Every control roll is a printed % in the caster's kit, rolled separately for each foe struck.

Elements

Every hero and foe carries an element from the first stage. Tide beats Pyre beats Stone beats Storm beats Tide; strike the element you beat for +10% damage. The Bloodline and the night sky add more on top from stage 25.
Elemental riders: every special carries a small mark of its caster's element. Fire scorches a burn, Storm adds +10% crit chance to the cast (additive), Tide mends your weakest ally, Stone braces the caster against the next blow.

Other verbs

DOT: damage over time. A lingering wound that keeps burning each beat after the hit, fading slowly.
Taunt: forces enemies to strike the taunting unit while it holds.
Redirect: a protector takes a share of the damage aimed at allies (Hector redirects 30%).
Revive: once per battle, a favored unit returns from a killing blow (Apollo raises Hector at 60% HP).