First pair of emigrants joining crowd in Victoria, say (7)
I believe the answer is:
empress
'victoria say' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'first pair of emigrants joining crowd' is the wordplay.
'first' is a charade indicator (letters next to each other).
'pair of emigrants joining' becomes 'em' (I can't explain this - if you can you should believe this answer much more).
'crowd' becomes 'press' (press is a kind of crowd).
'em'+'press' is 'EMPRESS'.
'in' acts as a link.
(Other definitions for empress that I've seen before include "Powerful woman" , "Josephine, for instance" , "Catherine the Great, for example" , "1 across was from 1877" , "She rules over vast territories" .)