Taxonomy of meanings for 一時:  

  • MOMENT
    • NPadSat a certain time; once upon a time
  • TIME
    • NPadSindefonce upon a time (don't ask me when exactly!)
    • NPadSpastBuddhist, idiomatic: at a certain time in the past ("once upon a time" would imply that fictitiousness is implied and acknowledged. Whether it is remains a subtle open isue. The fictitiousness is in any case not openly acknowledged.)
  • TOGETHER
    • NPadVat one time > at the same time, together; unisono
  • IMMEDIATELY
    • NPadVpresentat the time defined by a contextually determinate other event (expressed in S) > at once, immediately