A starting point, thats a fact (5)
I believe the answer is:
datum
This clue could be a double definition.
'a starting point' is the first definition.
'datum' can be an answer for 'point' (thesaurus). I am not sure about the 'a starting' bit.
'a fact' is the second definition.
(singular form of 'data')
'thats' is the link.
Can you help me to learn more?
(Other definitions for datum that I've seen before include "given to the Romans" , "Fact or stat" , "Bit of dope" , "Given piece of information" , "Given item" .)