Translation according to P. W. Joyce:
Ballynalack in Armagh and King's Co., Ballynalickin Tipperary, and Ballynalacka in Galway ; Baile-na-leice, the town of the flagstone. But the Bally here may in some cases represent Beal-atha, a ford: see Bally. See Ballinalack, vol. i. pp. 416, 417 [reproduced below].
The word leac, lic, or liag [lack, lick, leeg] - for it is written all three ways - means primarily a great stone, but it is commonly applied to a flag or large flat stone; thus the Irish for ice is leac-oidhre [lack-ira], literally snow-flag. The most ancient form is liac or liacc, which is used to translate lapis in the Wb. and Sg. MSS. Of Zeuss; and it is cognate with the Welsh llech; Lat. Lapis; and Greek lithos. This word occurs very often in Irish names, and in its local application it is very generally used to denote a flat-surfaced rock, or a place having a level rocky surface. Its most common forms are Lack, Leck, and Lick, which are the names of many townlands and villages through Ireland, as well as the diminutives Lackeen and Lickeen, little rock. The form liag is represented by Leeg and Leek in Monaghan, and by Leeke in Antrim and Londonderry. Lickmolassy, a parish in Galway - St. Molaise's flag-stone - was so called, because the hill on which the church was built that gave name to the parish, is covered on the surface with level flag-like rocks. Legvoy, a place in Roscommon, west of Carrick-on-Shannon, is called by the Four Masters Leagmhagh [Legvah], the flag-surfaced plains. The celebrated mountain Slieve League in Donegal, is correctly described by its name: - "A quarry lately opened here, shows this part of the mountain to be formed of piles of thin small flags of a beautiful white colour… And here observe how much there is in a name; for Slieve League means the mountain of flags". (From "Donegal Highlands". Murray and Co., Dublin.) I have already observed (p. 355) that stony fords are very often designated by names indicating their character; and I will give a few additional illustrations here. Belleek in Fermanagh, on the Erne, east of Ballyshannon, is called in Irish authorities, Bél-leice [Bellecka] "translated os rupis by Philip O'Sullivan Bear in his history of the Irish Catholics. The name signifies ford-mouth of the flag-stone, and the place was so called from the flat-surfaced rock in the ford, which, when the water decreases in summer, appears as level as a marble floor" (O'Donovan, Four Mast. V., p. 134). Belleek is also the name of a place near Ballina in Mayo, which was so called from a rocky ford on the Moy; there is a village of the same name near Newtown Hamilton. Armagh, and also two townlands in Galway and Meath. Ballinaleck is the name of a village in Westmeath, a name originally applied to a ford on the river Inny, over which there is now a bridge; the correct name is Bel-atha-na-leac [Bellanalack], the mouth of the ford of the flag-stones, a name that most truly describes the place, which is covered with limestone flags. In some other cases, however, Ballinalack is derived from Baile-na-leac the town of the flag-stones. Several derivative forms from leac are perpetuated in local names; one of these, leacach, signifying stony, is applied topographically to a place full of stones or flags, and has given the name of Lackagh to many townlands in different parts of Ireland. Several places of this name are mentioned in the annals; for instance, Lackagh in the parish of Innishkeel, Donegal, and the river Lackagh, falling into Sheephaven, same county, both of which are noticed in the Four Masters. 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.