Translation according to P. W. Joyce:
Esker ; a sand hill: see vol. i. p. 402 [reproduced below].
Eiscir [esker] means a ridge of high land, but it is generally applied to a sandy ridge, or a line of low sand-hills. It enters pretty extensively into local names, but it is more frequently met with across the middle of Ireland than in either the north or south. It usually takes the form of Esker, which by itself is the name of more than thirty townlands, and combines to form the names of many others; the word is somewhat altered in Garrisker, the name of a place in Kildare, signifying short sand-ridge. The most celebrated esker in Ireland is Esker-Riada, a line of gravel-hills extending with little interruption across Ireland, from Dublin to Clarin-Bridge in Galway, which was fixed upon as the boundary between the north and south halves of Ireland, when the country was divided, in the second century, between Owen More and Conn of the Hundred Battles (see p. 134). As a termination, this word assumes other forms, all derived from the genitive eiscreach [eskera]. Clashaniskera in Tipperary is called in Irish Clais-an-eiscreach, the trench or pit of the sand-hill. Ahascragh in Galway signifies the ford of the esker; but its full name as given by the Four Masters is Ath-eascrach Cluain [Ahascra Cuan], the ford of St. Cuan's sand-hill; and they still retain the memory of St. Cuan, the patron who is commemorated in O'Clery's Calendar at the 15th of October; Tiranascragh, the name of a townland and parish in Galway, the land of the esker. Eskeragh and Eskragh are the names of several townlands in the Ulster and Connaught counties, the Irish Eiscreach signifying a place full of eskers or sand-hills.