A sixteenth note is a musical note that lasts for one-fourth the duration of an eighth note. In standard music notation, it is represented by a filled-in oval note head with two flags or beams attached. Sixteenth notes are often used in fast-paced music to create a sense of rhythm and movement. In a measure of 4/4 time, there can be up to 16 sixteenth notes. They are commonly grouped in sets of four, making it easier to read and play. Musicians often use sixteenth notes to add complexity and texture to their compositions, enhancing the overall sound of the piece.