A big wheel in the fairground business (6)

I believe the answer is:

ferris

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

'a big wheel' is the definition.
'Ferris' can be an answer for 'wheel' (thesaurus). I'm unsure of the 'a big' bit.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for ferris that I've seen before include "Wheel such as the Eye" , "Kind of wheel" , "Inventor of fairground wheel ride" , "Giant revolving wheel at funfair" , "Big passenger-carrying wheel at circus or funfair" .)

Want a hint initially instead of a full solution? Install my app