Why is it called sharp?

The term "sharp" in music refers to the raising of a note by one semitone. It comes from the Latin word "acutus", meaning "pointed" or "sharp", and was originally used to describe the shape of the symbol used to notate a sharp note.

The sharp symbol (#) is thought to have evolved from a combination of two symbols: the Greek letter sigma (Σ) and the Latin letter b. The sigma was used in medieval notation to indicate a raised note, and the b was used to indicate a lowered note. Over time, the two symbols merged into the sharp symbol we use today.

The term "sharp" is also used to describe the sound of a note that has been raised by one semitone. A sharp note is typically perceived as being brighter and more piercing than a natural note, and is often used to create a sense of tension or excitement in music.