One serving queen or Medici, perhaps? (5)
I believe the answer is:
drone
'one serving queen' is the definition.
'drone' can be an answer for 'queen' (thesaurus). I'm not certain of the 'one serving' bit.
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for drone that I've seen before include "Continuous sound; bee" , "mollusc" , "Hum; monotonous talk" , "Idle fellow" , "Idle type" .)