n.

1. 形成，构成，组成[U]
   the formation of one's character

   性格的形成

2. 构成物；形态，结构[C][U]
   Clouds are formations of condensed water vapor.

   云是水汽凝聚而成。

3. 队形；阵式[U][C]
   They marched in parade formation.

   他们以列队的阵式行进。

n.

1. the action of forming or the process of being formed.
2. a thing that has been formed; a structure or arrangement.
   ▸a formal arrangement of aircraft in flight or troops.