One unknown Homer translation about rootstalk (7)
I believe the answer is:
rhizome
'rootstalk' is the definition.
(synonyms)
'one unknown homer translation' is the wordplay.
'one' becomes 'i' (Roman numeral).
'unknown' becomes 'z' (algebra).
'translation' is an anagram indicator.
'i'+'z'+'homer'='izhomer'
'izhomer' with letters rearranged gives 'RHIZOME'.
'about' is the link.
(Other definitions for rhizome that I've seen before include "Subterranean plant stem" , "Root" , "Underground plant stem producing roots and shoots - zero him (anag)" , "that supplies stock" , "Underground rootstock of a plan" .)