Steps look sound (5)
I believe the answer is:
stair
'steps' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'look sound' is the wordplay.
'look' becomes 'stare' (staring is a kind of looking).
'sound' shows a homophone (sound like).
'stare' is a homophone of 'STAIR'.
Can you help me to learn more?
(Other definitions for stair that I've seen before include "Support on which to step" , "Indoor step" , "Set of steps" , "Rising step" , "this could get one down" .)