An absolute encoder is a type of rotary or linear encoder that provides a unique position value for each specific position of the shaft or moving part. Unlike incremental encoders, which only detect changes in position, absolute encoders can determine the exact position without needing to move to a reference point or home position.

Key features of an absolute encoder include:
1. Unique Code for Each Position:** Each position corresponds to a distinct digital or analog code.
2. No Need for Re-Initialization:** Even after power loss, the encoder retains its position information.
3. High Precision:** They offer accurate position feedback, essential for applications requiring precise control.
4. Types:** They can be optical, magnetic, or capacitive, depending on the sensing technology used.

Applications of absolute encoders include robotics, CNC machines, elevators, and other systems requiring precise position control and reliability.