One takes in what may be a Scotsman's own (3)
I believe the answer is:
ain
'own' is the definition.
(synonyms)
'one takes in' is the wordplay.
'one' becomes 'a' (a thing is one thing).
'takes' says to put letters next to each other.
'a'+'in'='AIN'
'what may be a scotsman's' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for ain that I've seen before include "Glaswegian personal" , "Own (Scot)" , "The Scot's own" , "Your own in Scottish dialect" , "26 [ ]" .)