Ringfort, enclosure. Written Lis, Liss — the same Irish word, lios, in the spellings English gave it.
Lios is a ringfort: the circular earthen bank and ditch inside which an early medieval farming family lived, of which tens of thousands survive as 'fairy forts' in fields across Ireland. A Lis- name (Lisdoonvarna, Lismore) marks one, usually with a description of it. Because the forts were left alone for fear of the fairies, the name often outlived any memory of the people who built it.
Source: P. W. Joyce, The Origin and History of Irish Names of Places (1869–1913) · Logainm ↗
Ringfort, enclosure: it is the Irish lios. Lios is a ringfort: the circular earthen bank and ditch inside which an early medieval farming family lived, of which tens of thousands survive as 'fairy forts' in fields across Ireland. A Lis- name (Lisdoonvarna, Lismore) marks one, usually with a description of it.
lios. English spellings of the same word include Lis, Liss, because the names were written down by ear.
Lisburn (Lios na gCearrbhach), Lisnaskea (Lios na Scéithe), Listowel (Lios Tuathail).