Frank Sinatra's music is primarily categorized as traditional pop, which is a style of popular music that predates rock and roll. He is also strongly associated with jazz, particularly the swing subgenre of jazz, which was prominent in the '20s and '30s. His extensive musical career included recordings and performances in several genres, including traditional pop, swing, jazz, rhythm & blues (R&B), and even bolero. While his bulk of work leans towards jazz and traditional pop, his versatility made it difficult to confine him to any single genre. For example, some of his well-known hits like "New York, New York" and "Fly Me to the Moon" fall into swing, while "That's Life" leans towards R&B, and "Somethin' Stupid" is considered a bolero duet with his daughter Nancy Sinatra. Sinatra's music is known for its emotional depth, smooth phrasing and vocal control, making his genre classification quite broad and encompassing a rich variety of musical styles. In summary, if one had to pick a single genre, traditional pop is the most fitting, but jazz (especially swing), R&B, and bolero are also significant parts of his musical legacy. This versatility contributed to his status as one of the most successful and influential music artists of the 20th century.