One Note Samba
The song title refers to the main melody line, which at first consists of a long series of notes of a single tone (typically D, as played in the key of G) played over a descending chord progression in a bossa nova rhythm. The first eight measures consist of D, followed by four measures of G, and then four measures of D. This is followed by eight measures of a more conventional, scalar melody line.
This well-known song first reached a wide audience on the Grammy-winning bossa nova LP Jazz Samba (Getz/Byrd/Jobim), which reached the number one spot on the Billboard 200 in 1963. Another well-known release is the Sergio Mendes-Brasil '66 version, in medley with "Spanish Flea".