| once(adjective, adverb, past, then, previously) |
| time |
| at one point(time, moment, period, interval, duration) |
| at one time(expression, idiom, late, earlier, before) |
| away back(expression, late, earlier, before, once) |
| back when(expression, late, earlier, before, once) |
| but once(expression, late, earlier, before, once) |
| in the old days(expression, idiom, late, earlier, before) |
| in the olden days(expression, idiom, late, earlier, before) |
| in times gone by(expression, idiom, late, earlier, before) |
| in times past(expression, idiom, late, earlier, before) |
| long ago(expression, late, earlier, before, once) |
| old(late, earlier, then, before, once) |
| once only(expression, late, earlier, before, once) |
| once upon a time(expression, idiom, late, earlier, before) |
| one(late, earlier, then, before, once) |
| one time before(expression, idiom, late, earlier, before) |
| one time previously(expression, idiom, late, earlier, before) |
| only one time(expression, idiom, late, earlier, before) |
| single time(expression, late, earlier, before, once) |