A skerry is a small rocky island, usually defined to be too small for habitation. It may simply be a rocky reef.
The term skerry is derived from the Old Norse sker, which means a rock in the sea. The Old Norse term sker was brought into the English language via the Scots language. It is a cognate of the Scandinavian languages' words for skerry – Icelandic, Faroese: sker, Danish: skær, Swedish: skär, Norwegian: skjær / skjer and Finnish: kari. In Scottish Gaelic, it appears as sgeir, e.g. Sula Sgeir.
The “inside passage” provides a similar route from Seattle, Washington to Skagway, Alaska. Yet another such skerry-protected passage extends from the Straits of Magellan north for 800 km (500 miles). The Swedish coast along Bohuslän is likewise skerry guarded. Even the east coast of Sweden, in the Baltic sea has many big skärgårdar (archipelago) , notably Stockholm archipelago - Stockholms skärgård - skjærgård.
In the Russian Federation the best examples are the Minina Skerries, located in the Kara Sea, in the western shores of the Taymyr Peninsula, and the Sumsky Skerries (Sumskiye Shkhery) , located in the White Sea.
The United Kingdom has a large number of skerries including Staple Island (an Outer Farne Island) in England, a small rocky outcrop near the Fowlsheugh in northeast Scotland and numerous reefs in the Hebrides such as Dhu Heartach and Skerryvore.
The most southerly skerries are perhaps the Skrap Skerries off of South Georgia.
For a list of the various islands and island groups with skerry or skerries as part of their name see: The Skerries.