A musical phrase is a short segment of music that expresses a complete thought, similar to a sentence in language. It typically consists of a series of notes that create a recognizable melody or idea. Phrases can vary in length but often last for four or eight measures, making them easy to identify within a piece. In composition, musical phrases are essential for building structure and coherence. They can be repeated, varied, or developed throughout a piece, contributing to the overall form. Composers like Ludwig van Beethoven and Johann Sebastian Bach skillfully used phrases to convey emotion and narrative in their works.