How is the directive "m.d." interpreted in musical notation?

The directive "m.d." in musical notation stands for "manu dextra," which translates from Latin as "with the right hand." This instruction is especially common in piano music, where clear indications for hand usage can guide the performer on which hand to use for a particular passage. Therefore, when you see "m.d.," it clearly instructs the musician to play using the right hand.

In the context of the other possible interpretations, "m.d." is not related to any directives regarding dynamics, such as playing softly or loudly, nor does it instruct to play with the left hand. Each of these interpretations serves a different function in music notation, but they do not pertain to the meaning of "m.d."