no no no. it is a great question. LOD is short for lift-off-distance, which is a metric that tells us how far off the ground a mouse will still track. (typically given in mm or CDs (1.2mm))
For example, the WMO will still track up to 1.2mm off the ground (or 1 CD), while the Deathadder will still track up to 4.8mm off the ground (or 4 CD).
This matters to people like me who lift up their mouse constantly. Lower is better so my cursor doesn't fly all over the place while I'm repositioning.
I couldn't stand to lift my mouse up... how can you do it?