Means princess with child has left (7)
I believe the answer is:
channel
'means' is the definition.
(I have seen 'means of communication' mean 'channel' so perhaps 'means' could also mean 'channel')
'princess with child has left' is the wordplay.
'princess' becomes 'anne' (Princess Anne, daughter of Queen Elizabeth).
'with' says to put letters next to each other.
'child has' becomes 'ch' (this could be a standard abbreviation which I don't know about).
'left' becomes 'l' (common abbreviation).
'anne' put after 'ch' is 'channe'.
'channe'+'l'='CHANNEL'
Can you help me to learn more?
(Other definitions for channel that I've seen before include "water-bed" , "vehicle" , "Communication medium" , "Water conduit or TV programme identifier" , "Furrow" .)