Logistics refers to provisioning armies with food, weapons, water, fodder, and so on in order to keep them in operation as a viable military unit.
Logistics in the SCA
While the logistics of feeding whole armies are rarely handled by SCA commanders, SCAdians who attend any of the Wars are familiar with the difficulties of logistical planning. Decisions about food, shelter, travel plans, etc. are all logisitcal decisions, and it is no fun at all when they don't work out.