Gaelic gille, Irish giolla, E. Ir, gillo, signifies a 'youth,' but now generally a servant, 'gillie.' 'Hence it happened that families who were devoted to certain saints, took care to call their sons after them, prefixing the word Giolla, intimating that they were to be the servants or devotees of those saints There were very few saints of celebrity, from whose names those of men were not formed by the prefixing of giolla This word was not only prefixed to the names of saints, but also to the name of God Christ, The Trinity, the Virgin Mary, and some were named from saints in general, as well as from the angels in general But when an adjective, signifying a colour or quality of the mind or body is postfixed to giolla, then it has its ancient signification namely, a youth, a boy, or a man in his bloom, as Giolla-dubh, the black or black-haired youth, Ginllo-ruodh, the red-haired youth, &c." (O'Donovan, AFM., III, p. 2—3.) When Mac was prefixed to gille the g was slurred over in order to obviate the harsh sound of the two consonants, hence the forms MacIl-and Maclli-, as in Gill' Sheathain, M'llleathan, and lastly, simple I for ill. The BBT., among others, shows extraordinary curtailments of this kind: M'Lechrist for M'lllle Chriosd; M'Levorri or Maklivorrie for M'Illemhoire; M'Lehoan for M'Gille Chomghain, S. Comgan; M'Lephadrick for M'lllephadraig; M'Lecheir for M'Gille-chiar; and Maklinoto for M'Gille-naoimh. Indeed l after Mac usually indicates a curtailed gille. Gille itself very commonly disappears from Gaelic names as Calum from Gillecalum, etc., which were originally not used as ordinary names without the prefix of gille or maol. Prof. Zimmer maintained (Gottingische gelehrte Anzeigrn, September I, 1891, p. 184) that the word ginua is not Irish but a loan from ON. gild-r, 'strong, brawny.' Marstrander, however, has clearly shown ('Altirische Personennamen mit gilla,' in Zeitschrift fur celtische Philnlogie, v. 13, p. 1—2) that the word antedates the Norse period.