1British a kind of folk music with a blues or jazz flavour that was popular in the 1950s, played by a small group and often incorporating improvised instruments such as washboards.
2US a style of 1920s and 1930s jazz deriving from blues, ragtime, and folk music, using both improvised and conventional instruments.
Origin:
1920s: perhaps imitative
skiffle in other Oxford dictionaries
Definition of skiffle in the US English dictionary