Name the musical symbol that indicates to raise a note by a half step.

The symbol that indicates to raise a note by a half step is the sharp symbol, represented by ♯. When placed before a note, it modifies the pitch by increasing it by one semitone (or half step). This is an essential concept in music notation, as it helps create varied melodies and harmonies by providing the means to adjust pitches.

In musical contexts, raising a note can change the sound and emotion of a piece, and understanding the role of sharps is vital for interpreting and performing music accurately. The ability to recognize this symbol and apply its impact is a fundamental skill in music theory.