at one time in WordNet English dictionary

1. simultaneously
   "he took three cookies at a time"
   at a time  at once  at one time  at a time  at once  at one time 
   
2. at a previous time
   "at one time he loved her"; "her erstwhile writing"; "she was a dancer once";
   once  formerly  at one time  erstwhile  erst  once  formerly  at one time  erstwhile  erst 
   

at one time in English Wiktionary