also: だいがえひん
noun
substitute; replacement; backup
A product or item used in place of another, often when the original is unavailable or as a spare.
純正部品がないので、代替品を使うしかなかった。
Since there were no genuine parts, we had no choice but to use a substitute.
災害時に備えて、代替品を用意しておく。
Prepare substitute items in case of a disaster.