: an artificial fortified island constructed in a lake or marsh originally in prehistoric Ireland and Scotland
The Irish word crannóg derives from Old Irish crannóc, which referred to a wooden structure or vessel, stemming from crann, which means “tree”, plus a diminutive ending—literally “young tree”. The modern sense of the term first appears sometime around the 12th century; its popularity spread in the medieval period along with the terms isle, ylle, inis, eilean or oileán. There is some confusion on what the term crannog originally referred to, as the structure atop the island or the island itself. The additional meanings of ‘crannog’ can be variously related as “structure/piece of wood; wooden pin; crow’s nest; pulpit; driver’s box on a coach and vessel/box/chest” for crannóg. The Scottish Gaelic form is crannag and has the additional meanings of “pulpit” and “churn”. Thus there is no real consensus on what the term crannog actually implies, although the modern adoption in the English language broadly refers to a partially or completely artificial islet that saw use from the prehistoric to the Post-Medieval period in Ireland and Scotland.