What is "turlough"

n. (context Ireland English) A temporary lake in an area of limestone, filled by rising groundwater during the rainy winter season.

Turlough can mean:

• Turlough (lake) disappearing lake found mostly in limestone areas of Ireland
• Turlough O'Brien (1009–1086) Anglicised form of Toirdelbach Ua Briain, King of Munster, effectively High King of Ireland
• Turlough Luineach O'Neill (1530–1595) Ulster chieftain
• Turlough MacShane O'Neill (died 1608), Irish landowner
• Turlough Ó Carolan (1670–1738) Irish harper
• Vislor Turlough, fictional character from Doctor Who
• Turlough, County Mayo, village in Ireland
• Turlough Hill, a mountain in Ireland

A turlough, or turlach, is a type of disappearing lake found mostly in limestone areas of Ireland, west of the River Shannon. The name comes from the Irish "tuar", meaning dry, with the suffix "lach", meaning a place (in an abstract sense). The "lach" suffix is often mistakenly spelled and/or thought to refer to the word "loch", the Irish, Scottish Gaelic and Scots word for lake. They are found in Irish karst (exposed limestone) areas.

The features are almost unique to Ireland, although there is one example in Great Britain in Llandeilo. They are of great interest to many scientists: geomorphologists are interested in how turloughs were formed, hydrologists try to explain what makes turloughs flood, botanists study the unusual vegetation which covers the turlough floor and zoologists study the animals associated with the turloughs.