Di-

-day; the prefix in the names of the days of the week, Irish, Old Irish dia, die (Old Irish), Welsh dydd, Cornish det (for dedh), Breton dez, dijas (*dejes-?); Latin diês; Sanskrit dyáús, day, sky; Greek $$GZeús, $$GDiós, Jove. Allied to dia, god. <Di-dòmhnuich>, Sunday, Irish Domhnach, Early Irish domnach, from Latin (dies) dominica, Lard's day - dominus, lord; <Di-luain>, Monday, Irish Dia-luain, Middle Irish luan, Welsh Dydd Llun, from Latin dies Lunæ, "day of the moon"; <Di-màirt>, Tuesday, Irish Dia-mairt, Early Irish máirt, Welsh Dydd mawrth, from Latin dies Martis, "day of Mars"; <Di-ciaduinn>, <Di-ciadaoin>, Wednesday, Irish Dia-céadaoine, Old Irish cétáin, cétóin, de cétain ( de = dia = Latin die), dia cetáíne, from ceud, first, and aoine, fast, q.v., Early Irish áine: "day of the first fast", Friday being the second and chief day; <Diardaoin>, Thursday, Irish Dia-dhardaoin, Early Irish dardóen = etar dá óin, "between two fasts" - the day between the two fasts of Wednesday and Friday; <Di-haoine>, Friday, Irish Dia-aoine, Dia-haoine, Early Irish áine, dia áine, Old Irish dia oine dídine (day of the last fast): "day of the fast", from aoine, fast, q.v.; <Di-sathuirn>, Saturday, Irish Dia-sathuirn, Middle Irish satharn, dia sathairn, from Latin dies Saturni, day of Saturn.. The days of the week were originally named (in Egypt) after the seven planets of the ancients - Sun, Moon, Mars, Mercury, Jove, Jove, Venus, Saturn.