duplication
🇺🇸
/ˌduːplɪˈkeɪʃn/
🇬🇧
/ˌdjuːplɪˈkeɪʃn/
making an exact copy of something
We avoid duplication by keeping one master file instead of making many copies.
doing the same thing again when not needed
This duplication of work wastes time and money.