Introduction to nephew, third and sixth cousins and sister (3)
I believe the answer is:
nun
'sister' is the definition.
(nuns are referred to as sister)
'introduction to nephew third and sixth cousins' is the wordplay.
'introduction to' indicates taking the first letters.
'third and' becomes 'u' (I can't explain this - if you can you should give a lot more credence to this answer).
'sixth cousins' becomes 'n' (6th letter of 'cousins').
The first letter of 'nephew' is 'n'.
'n'+'u'+'n'='NUN'
'and' is the link.
Can you help me to learn more?
(Other definitions for nun that I've seen before include "Convent dweller" , "Domestic fancy pigeon" , "She's made vows" , "Holy sister" , "One in holy order" .)