A Calendar is a system for organizing days for social, religious, commercial or administrative purposes. This is typically done by naming specific periods of time, typically days, weeks, months and years. A date is the designation of a single, specific day in such a system. Each civilization on Nakti has developed at least a rudimentary way of keeping track ot fime, whether by observing solar/lunar cycles, taking seasons into account, counting day/night cycles, or other means.