Elder for one right to fetch round support of course (4)
I believe the answer is:
tree
'elder for one' is the definition.
(elder is a kind of tree)
'right to fetch round support of course' is the wordplay.
'right' becomes 'r' (common abbreviation).
'to' means one lot of letters go next to another (I've seen this in other clues).
'round' means to look at the middle letters.
'support of course' becomes 'ee' (I can't justify this - if you can you should believe this answer much more).
The centre of 'fetch' is 't'.
'r' after 't' is 'tr'.
'tr'+'ee'='TREE'
(Other definitions for tree that I've seen before include "Conifer, for example" , "Large, woody perennial plant" , "Box, perhaps" , "Large growth" , "Box or bay maybe?" .)