Tick

From The EQMac Wiki

A tick is equivalent to six seconds and is the smallest unit of in-game time. The EverQuest client receives an update every tick. This is why an NPC's health does not seamlessly go down as your group kills it; for example, you will see 100%, 79%, 49%, 2%. Spells also function by ticks; the server stores all buff durations in ticks. And subsequently, when extended duration focus effects make buffs longer, the game will round to the nearest tick.