Meaning
A solid black circle, one of the original plain dots. It means black and often works as a bold, neutral bullet point.
It is great for minimal lists, dark colour themes and board games, since ⚫ and ⚪ together look like the stones in the game of Go: “Your move ⚫, I’m playing white” It can also mark an offline or unavailable status. For a smaller, lighter bullet, ▪️ is the better fit.