Lachlan (ˈlæxlən,_ˈlæklən,_ˈlɒklən) is a masculine given name, an Anglicised derivative from Irish Gaelic and Scottish Gaelic.
The name is an Anglicised form of the Scottish Gaelic Lachlann, which is in turn derived from the earlier Gaelic personal name Lochlann.
In the ninth century, the terms Laithlinn / Laithlind (etc.), appear in historical sources as terms denoting the origin of Vikings active in Ireland. The exact meaning behind these terms is uncertain. What is clear, however, is that the terms Lochlann / Lochlainn (etc.) came to replace these earlier terms; and that, by the eleventh century, Lochlann / Lochlainn certainly referred to Norway in historical sources. Whether the terms Lochlann / Lochlainn were originally related to Laithlinn / Laithlind, or merely conflated with them, is unknown. In mediaeval Irish literature, the term Lochlann refers to a vague faraway place: sometimes the Otherworld, and sometimes Scandinavia.
Pet forms of Lachlan include La