My lord takes horse, a mighty steed (5)
I believe the answer is:
shire
'a mighty steed' is the definition.
The answer and definition can be both animals as well as being singular nouns.
Maybe there's an association between them I don't understand?
'my lord takes horse' is the wordplay.
I cannot really see how this works, but
'horse' could be 'h' (abbreviation as in horse power) and 'h' is located in the answer.
'lord' could be 'sire' (sire is a kind of lord) and 'sire' is found within the remaining letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for shire that I've seen before include "Powerful draught horse" , "Berks" , "Rural county" , "English county" , "Breed of draught horse" .)