From Longman Dictionary of Contemporary Englishone day/morning/year etcone day/morning/year etca) TIME/AT A PARTICULAR TIMEon a particular day, morning etc in the past One morning I was sitting at my desk when a policeman knocked at my door. b) used to talk about a day, morning etc in the future which is not yet exactly known or decided We should go out for a drink one evening. One day she hopes to move to the South Coast. → one
Examples from the Corpus
one day/morning/year etc• Everything, all in one year.• I've always said you'd hurt yourself one day.• They may be more concerned about pain, or being sent home from the hospital after one day.• We prospectively followed up 50 patients with healed ulcers for one year.• In the tiny northern town of Sugar Hill, the police chief picks one day a month and issues tickets.• Mr Emery reopened his store one day after his arrest, and said he will sell marijuana seeds by mail order.• She remembered going with her father one day, and being dreadfully bored.• That includes one day, May 26, when the collar was invoked twice -- both on declines. 