What is the difference between well-tempered and equal-tempered tuning systems in music?

In music, the difference between well-tempered and equal-tempered tuning systems lies in how they distribute the tuning of notes across the musical scale. Well-tempered tuning adjusts the tuning of each note slightly to create harmonious intervals in specific keys, while equal-tempered tuning divides the octave into equal intervals, allowing for flexibility in playing in different keys without retuning.