Peninsula is a spacious piece of land, which seas surround from three sides.
Peninsula is a spacious piece of land, seas surround it from three sides.
Peninsula is a spacious piece of land, which is surrounded by seas from three sides.
Are the previous sentences correct?
Also, delete 'spacious'. It is meaningless.
A peninsula can be as big as Florida or as small as a few square metres.
Additionally, change 'seas' to 'water' as lakes and oceans have peninsulas, too.
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A better title would have been 'peninsula definition'.
Extract from the Posting Guidelines:
'Thread titles should include all or part of the word/phrase being discussed.'