Drop D tuning is a popular guitar tuning where the lowest string, usually tuned to E, is lowered one whole step to D. This adjustment allows for a deeper, richer sound and makes it easier to play power chords, as they can be played with a single finger across the lower three strings. In Drop D tuning, the other strings remain in standard tuning, which means the second string is still B, the third string is G, the fourth string is D, the fifth string is A, and the sixth string is now D. This tuning is commonly used in various music genres, including rock and metal.