Crossword Genius

Parent at the start of the sixth century? (3)

Ross

I believe the answer is:

dad

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

'parent' is the definition.
(dad can informally mean father)

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for dad that I've seen before include "Mum's mate" , "Pa" , "Papa" , "Popular father - a palindrome" , "Relation" .)

I've seen this clue in The Times.
Want a hint initially instead of a full solution? Install my app