A waltz is a melody played with three beats to the bar, usually in 3/4 or 3/8 time. Most waltzes are played in 3/4 time, and are found across the spectrum of musical styles.
Waltzes have been popular for centuries; many folk songs, lullabies and hymns are set to waltz tunes, as are a surprising number of pop tunes, as waltz time would not at first appear to be used often in popular songs. The strong first beat and easy to follow rhythm with one musical chord per bar may account for the waltz’s enduring popularity.
Fast waltzes are played in 3/8 time. These were popularized in Vienna towards the end of 18th Century. The Strauss family was influential in the rising popularity of waltz music, particularly Johann Sebastian Strauss, whose enduring waltz melodies are still frequently played and danced to today.
A hesitation waltz, named for a slight delay while interpreting the measure, adds challenge for singers and dancers and interest for their listeners and observers.