Sharp

A sharp is when a note is one half-step higher. For example, the note "F" one half step is "F sharp". Sharp notes are accidentals and carry throughout the entire measure if one note does not have a natural or other accidental sign before it. Sharps are the direct opposite of flats.

Double Sharps
Double sharps raise a note by two half steps or semitones. So C double sharp would be D. Remember, two half steps equal one whole step.

Triple Sharps
Triple sharps raise a note by two and half half-steps or one and a half whole steps. In this case "C" would become D# or Eb.