Round Disk in Board Games? It's Called a Counter (or Token, Meeple, Pawn)

You're likely thinking of a counter (also token, marker, pawn, meeple).

Common Uses

• Player Position: Track location on a track or map.
• Resources: Represent money, VP, health, mana, goods.
• Units/Armies: In wargames, each counter = a military unit.
• Status Markers: Stunned, poisoned, upgraded, etc.
• Action Selection: Place on action spaces (worker placement).

Variations

• Meeple: Stylized human-shaped wooden token (Carcassonne popularized).
• Cube: Wooden/plastic cube (Eurogames standard).
• Cardboard Chit: Punched counters with printed info (wargames).
• Miniature: Detailed plastic figure (RPGs, miniatures games).

If you have more clues (game name, shape, color, text on it), I can be more specific!