A specimen or illustration (7)
I believe the answer is:
example
This clue is a double definition.
'a specimen' is the first definition.
(I've seen this before)
'illustration' is the second definition.
(synonyms)
'or' acts as a link.
(Other definitions for example that I've seen before include "Illustrative case" , "Illustration or paradigm" , "warning" , "Specimen, sample" , "Something to be imitated" .)