The Dutchman, say, regularly likes doin' smoke rings (4,4)

I believe the answer is:

folk song

I'm a little stuck... Click here to teach me more about this clue!

'smoke rings' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.

I don't understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for folk song that I've seen before include "Traditional ballad" , "eg 'The Lincolnshire Poacher'" .)

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.