Tick

From EQ KnowledgePit

Classically speaking, the game operates entirely in ticks. Spell duration, DoT/HoT spells, regeneration, etc. A tick occurs every six seconds. This means that all spells' duration is in multiples of six seconds; additionally, HP/Mana/Endurance regeneration all take effect once every six seconds.

In the modern game, there are a number of aspects of the game that do not rely on the tick system. Cooldown timers for disciplines, for instance, operate on a per-second basis.