Father, holding key, joins the French race (6)
I believe the answer is:
people
'race' is the definition.
(I've seen this before)
'father holding key joins the french' is the wordplay.
'father' becomes 'pop ' (pop is a kind of father).
'holding key' becomes 'e' (musical key. I am not sure about the 'holding' bit.).
'joins' indicates putting letters inside (inserted letters join the word).
'the french' becomes 'le' ('the' in French).
'pop' enclosing 'e' is 'peop'.
'peop'+'le'='PEOPLE'
Can you help me to learn more?
(Other definitions for people that I've seen before include "country folk" , "Men, women and children" , "Newspaper" , "Race - mankind" , "See 6" .)