Mouths use satire in a new way (9)
I believe the answer is:
estuaries
'mouths' is the definition.
The definition and answer can be both natural objects as well as being plural nouns.
Maybe you can see a link between them that I can't see?
'use satire in a new way' is the wordplay.
'in a new way' indicates anagramming the letters.
'use'+'satire'='usesatire'
'usesatire' with letters rearranged gives 'ESTUARIES'.
Can you help me to learn more?
(Other definitions for estuaries that I've seen before include "coastal features" , "Tidal river mouths" , "Broad mouths of rivers" .)