a.[Z]

1. 后面的；尾部的；背部的[B]
2. 较晚的，以后的[F][（+to）]
3. 其次的
4. 【植】近茎轴一侧的，后面的

n.

1. 后部；臀部[C]
   He paused a moment to raise his posterior from the chair.

   他停顿了一下，从椅子上立起来。

adj.

1. chiefly Anatomy  further back in position; of or nearer the rear or hind end. The opposite of anterior.
2. Medicine  relating to or denoting presentation of a fetus in which the rear or caudal end is nearest the cervix and emerges first at birth.
3. formal coming after in time or order; later.

n.