A sword of mine (8)
I believe the answer is:
claymore
I believe this is a double definition.
'a sword' is the first definition.
(I know that claymore is a type of sword)
'mine' is the second definition.
(I know that claymore is a type of booby trap)
'of' acts as a link.
(Other definitions for claymore that I've seen before include "Scottish sword wielded by my oracle" , "Highland sword" , "Highland weapon" , "Scottish two-edged sword" , "mine, sort of" .)