n.

1. 减少；削减[U][C][（+in）]
   reduction of household expenses

   家用开支的削减

2. 缩小[U][C][（+in）]
3. 下降，降低；降级[U][（+to）]
   reduction of an embassy to a liaison office

   大使馆降级为联络处

4. 缩图，缩版[C]
5. 转换，变化[U][（+to）]
   reduction to ashes

   化为灰烬

6. 归纳；简化[U][（+to）]
7. 【数】简化，约化[U][C]
8. 【化】还原（作用）[U][C]

n.

1. the action of reducing.
   ▸the amount by which something is reduced.
2. an arrangement of an orchestral score for piano or a smaller group of performers.
3. a smaller copy of a picture or photograph.
4. a thick and concentrated liquid or sauce.