A half rest is a musical symbol that indicates a silence lasting for two beats in a measure. It looks like a small rectangle sitting on top of a line, resembling a hat. Musicians use half rests to create pauses in their music, allowing for a break in sound while maintaining the rhythm. In standard music notation, half rests are often found in various time signatures, such as 4/4 or 3/4. They are essential for composers and performers to communicate when to rest, ensuring the music flows smoothly and maintains its intended structure.