A tick refers to one of two things:

  • A 20 minute period in which bounties are collected and distributed -- It can be used to measure efficiency when comparing two different isk making activities or comparing payout of running the same activity multiple times.
  • Alternatively, it refers to a server tick, the one second periods of time that tranquility operates on. Every action in EVE Online is calculated in one second server ticks and updates are sent to clients based on the events of the previous tick. If a ship is trying to escape a gatecamp, an align time of 1.4 seconds to 1.7 makes no difference, but the difference between 2.1 seconds and 1.7 reduces the "Ticks" you're visible by one, potentially letting you beat a gate camp.