Sea and shore - or just the shore (8)
I believe the answer is:
mainland
'just the shore' is the definition.
I can't judge whether this definition defines the answer.
'sea and shore' is the wordplay.
'sea' becomes 'main' (synonyms).
'and' means one lot of letters go next to another.
'shore' becomes 'land' (synonyms).
'main'+'land'='MAINLAND'
'or' is the link.
Can you help me to learn more?
(Other definitions for mainland that I've seen before include "A country excluding its adjacent islands" , "Area excluding offshore islands" , "Country or continent, as distinguished from an island" , "Principal part of a country, not an island" , "A country's principal as opposed to its islands" .)