In music theory, a "sharp" is a symbol (♯) that raises the pitch of a note by a half step. For example, if you play a C note and then play C♯, the latter is a half step higher. Sharps are commonly used in various musical scales and keys, particularly in major and minor scales. Sharps are often found in the key signature of a piece of music, indicating which notes should be played higher throughout the composition. In the circle of fifths, each sharp added corresponds to a new key, helping musicians understand the relationships between different keys and their respective sharps.