This article is incomplete and waiting on someone to expand it.
Star can have multiple meanings:
A stage in a beatmap's
forum modding process where a moderator judges a beatmap to be on the right track but needing some improvements before approve with a
bubble.
Examples include adjustments in timing, incorrect beat spacing in some areas, or creating additional difficulty versions.
Beatmaps receiving a star are denoted by a star graphic next to their thread's title.
A star may be removed by another mod if the beatmap is thought to be in need of more improvements.
Another term for "Star Rating".