A grace note is a musical ornament that is played just before the main note. It adds expressiveness and embellishment to a melody, often making it more interesting. Grace notes are typically not counted in the rhythm of the piece, meaning they are played quickly and lead into the main note. In sheet music, grace notes are usually notated as small notes before the main note they precede. They can be found in various styles of music, including classical, jazz, and folk. Musicians often use grace notes to enhance their performance and convey emotion, making them an important aspect of musical expression.