In volleyball, the libero is a specialized defensive player focused on receiving serves and making digs (defensive saves) from spikes or other attacks. Introduced by the FIVB (International Volleyball Federation) in 1998, the libero plays a unique role:

1. Defensive Specialist: The libero is typically the best defensive player on the team and excels at keeping the ball in play.

2. Restricted Positioning: They are not allowed to spike the ball if it is above the net or serve the ball. The libero only plays in the back row and cannot participate in front-row attacks or blocks.

3. Different Uniform: To be easily identifiable, the libero wears a different-colored uniform from the rest of the team.

4. Unlimited Substitutions: Unlike other players, the libero can substitute in and out freely without prior notification to the referee, usually rotating with a middle blocker when the team moves into a defensive position.

5. Ball Control and Passing: Liberos are critical in receiving serves and setting up offensive plays from the backcourt, allowing the team to maintain stability and control during rallies.