Translation according to P. W. Joyce:
Corlackan in Galway; round hill of the leaca or hill-slope. See Leaca, vol. i. p. 418 [reproduced below].
Leacan is one of the most widely extended of all derivatives from leac, and in every part of the country it is applied to a hill-side. In the modern forms of Lackan, Lacken, Lackaun, Leckan, Leckaun, and Lickane, it gives name to more than forty townlands, and its compounds are still more numerous. Lackandarra, Lackandarragh, and Lackendarragh, all signify the hill-side of the oak; Ballynalackan and Ballynalacken, the town of the hill-side. Lackan in the parish of Kilglass in Sligo was formerly the residence of the Mac Firbises, where their castle, now called Castle Forbes (i.e. Firbis), still remains; and here they compiled many Irish works, among others, the well known Book of Lecan. The form Lacka is also very common in local names, with the same meaning as leacán, viz., the side of a hill; Lackabane and Lackabaun, white hill-side. The two words, leaca and leacán, also signify the cheek; it may be that this is the sense in which they are applied to a hill-side, and that in this application no reference to leac, a stone was intended.