Governs, yet somehow holds one dominion (11)
I believe the answer is:
sovereignty
'dominion' is the definition.
(sovereignty is a kind of dominion)
'governs yet somehow holds one' is the wordplay.
'somehow' indicates anagramming the letters.
'holds' means one lot of letters goes inside another.
'one' becomes 'i' (Roman numeral).
'governs'+'yet'='governsyet'
'governsyet' anagrammed gives 'soveregnty'.
'soveregnty' placed around 'i' is 'SOVEREIGNTY'.
(Other definitions for sovereignty that I've seen before include "Self-government" , "it rules!" , "Pre-eminence" .)