What is "lochlann"

Lochlann (earlier Laithlind) is a geographical region in Classical Gaelic literature and in the history of Early Medieval Ireland. In the modern Gaelic and Welsh (Llychlyn) languages it signifies Scandinavia, and more specifically Norway. In Irish, the adjectival noun "Lochlannach" (person belonging to Lochlann) has the additional sense of "raider", specifically, Vikings.