Lepton

A lepton is a distance measuring unit, which equals 1/256th of a map cell's edge. So, a single map cell is 256x256 leptons. In other words, if you were to draw a circle (in the game's pseudo-isometric perspective) inside the boundaries of a map cell, the diameter of that circle would be exactly 256 leptons.

This unit is used to measure object Firing Offsets, animation draw offsets, and such distances which require a high level of sub-cell precision.