Origin: 1200–50; (v.) Middle English sojurnen < Old French sojorner to rest, stay < Vulgar Latin *subdiurnāre, equivalent to Latin sub-sub- + diurn(us) of a day + -āre infinitive suffix; (noun) Middle English sojurne < Old French sojorn, derivative of the v.; see journey
late 13c., from O.Fr. sojorner "stay or dwell for a time," from V.L. *subdiurnare "to spend the day," from L. sub- "under, until" + diurnus "of a day," from diurnum "day" (see diurnal). French séjourner formed via vowel dissimilation.