Someone you share a line with (8)
I believe the answer is:
ancestor
'someone' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe there's a link between them I don't understand?
'share a line with' is the wordplay.
I cannot really see how this works, but
'a' could be 'an' and 'an' is found within the answer.
This explanation may well be incorrect...
'you' is the link.
Can you help me to learn more?
(Other definitions for ancestor that I've seen before include "Antecedent, forebear" , "Predecessor" , "Old member of the family -no traces (anag)" , "Forefather" , "not being of the modern generation" .)