Here’s a definition of Hambo from Wikipedia:

The hambo is a traditional dance that originated in Sweden in the late 19th and early 20th centuries. It is a couple dance in ¾ time, danced to music played with a strong accent on the first beat and a tempo that varies from moderate to fast (100 to 120 beats per minute). The hambo is a dance with a fixed pattern and tunes almost always have a corresponding eight measure structure.

In Sweden, the hambo is in the gammaldans (old-time dance) tradition that, despite the name, arose fairly recently around the beginning of the 20th century. The dance is also danced in North America in the social clubs formed by immigrant Swedes and during breaks at contradance venues. Many social waltz groups include the hambo among their regular dances.