Little house on top of a dam (6)
I believe the answer is:
hoover
'a dam' 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?
'little house on top' is the wordplay.
'little' suggests taking the first letters.
'top' becomes 'over' (I've seen this before).
The first letters of 'house on' is 'ho'.
'ho'+'over'='HOOVER'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for hoover that I've seen before include "US president in House throughout" , "US president, 1929-33" , "Former president of US and vacuum cleaner" , "J Edgar . . . . . . was FBI chief" , "Vacuum-cleaner" .)