In Star Wars, a "rotation" refers to a planets rotation around its sun, essentially a day. However, it is not specified which planets rotation is used as the standard measurement. It is likely that rotations in Star Wars are based on the rotations of the Core World of Coruscant, as it was the capital of both the Republic and the Empire. The length of a "rotation" can vary greatly depending on the planet, with some planets having rotations that last the equivalent of many standard days. When characters in Star Wars talk about a "rotation" without any further context, they are usually referring to one standard day, the amount of time it takes for Coruscant to perform one complete turn around its axis. However, on other occasions, they may refer to a "rotation" to mean one local day/night cycle, which can range from just a few hours up to hundreds of days depending on the planetary system.