ar‧chi‧pel‧a‧go /ˌɑːkəˈpeləɡəʊ, ˌɑːkɪˈpeləɡəʊ $ ˌɑːrkəˈpeləɡoʊ/ noun (plural archipelagos) [countable]
[Date: 1600-1700; Origin: Archipelago 'Aegean sea' (16-19 centuries), from Italian, 'main sea', from arci- (from Latin archi-; ⇒ arch-) + Greek pelagos 'sea']
a group of small islands

[TahlilGaran] Dictionary of Contemporary English ▲

island a piece of land completely surrounded by water:
We visited the Greek island of Kos.
In the centre of a lake is a small island.
isle an island – used in poetry or in names of islands:
The horse carried him to the windswept isle of Bujan.
It is the most southerly point in the British Isles.
the Windward Isles
the Isle of Wight
peninsula a piece of land almost completely surrounded by water but joined to a large area of land:
There is a coastal path around the peninsula.
the Korean peninsula
archipelago a group of small islands that are in a line:
He lives on an island at the eastern end of the Indonesian archipelago.

[TahlilGaran] English Thesaurus ▲