A half note is a musical symbol that represents a specific duration of sound in music. It is typically held for two beats in common time, which is often represented by the time signature 4/4. The half note is visually depicted as a hollow oval note head with a stem, distinguishing it from other note types like the quarter note and whole note. In sheet music, half notes are used to create rhythm and melody. Musicians play half notes for a longer duration than quarter notes, allowing for a more sustained sound. Understanding half notes is essential for reading music and performing accurately in various musical genres.