Sea's inlets eroding main points (10)
I believe the answer is:
essentials
'main points' is the definition.
The answer and definition can be both natural objects as well as being plural nouns.
Perhaps they are linked in a way I don't understand?
'sea's inlets eroding' is the wordplay.
'sea's inlets' can be anagrammed to 'ESSENTIALS'.
However, I'm unsure how this is indicated.
Can you help me to learn more?
(Other definitions for essentials that I've seen before include "necessities" , "Things needed" .)