Which term signifies "sad, mournful" in music?

The term that signifies "sad, mournful" in music is "mesto." This Italian word is often used in compositions to evoke a sense of melancholy or sorrow. Composers may indicate "mesto" to guide performers in conveying a specific emotional character throughout a piece, enhancing the expressiveness of the music.

In contrast, "mässig" refers to a moderate tempo, which does not convey a specific emotional quality. "Mezzo piano" indicates a medium soft dynamic level but does not imply sadness. "Marcato," meaning marked or emphatic, suggests a strong and pronounced manner of playing, quite the opposite of a mournful character.