The term was certainly in use in England in the late 1960s - early 1970s. It was used fairly loosely, but would probably be made up of people from the folk song and morris side of the folk scene rather than "proper" dancers, and would probably involve one or two song spots or morris displays.

Wot he said. The first ceilidh I went to was in 1976 (or possibly 75), and featured the Albion Dance Band (as they then were). I don't remember a thing about it, as I'd got comprehensively pissed on the road crew's London Pride earlier in the day. I had a good time, or so people told me afterwards.