臀部的英文：
butt
buttocks

参考例句：

The rump of a horse; the croup.
马臀;四脚动物的臀部.

Across the internet, chat rooms, web sites and blogs have sprung up discussing buttock injections.
互联网上，聊天室里，网站和博客上都涌现出关于臀部注射的讨论。

Armor consisting of overlapping plates used to protect the buttocks
护臀甲由相互交迭的甲片构成的铠甲，用来保护臀部

Any of the three large muscles of each buttock,especially the gluteus maximus,that extend,abduct,and rotate the thigh.
臀肌每侧臀部的三块大肌肉之一，尤指延展并围着大腿部的最大的一块臀肌

Voluptuous breasts,hips,curves
丰满的乳房、臀部、曲线

An injection in the Buttock
注射在臀部的一针

My seat is rather sore from riding a horse.
我骑马骑得臀部很酸痛。

The pants is too tight across the seat .
这短裤的臀部太紧了。

The region of the hips,groin,and lower abdomen.
臀部、腹股沟和下腹部区域

`Arse' is a vulgarism for the buttocks.arse
是用以指臀部的粗俗词.

butt是什么意思：
n. 笑柄；烟头；靶垛；大酒桶；屁股；粗大的一端
v. 以头抵撞

I was the butt of their jokes.
我是他们的笑柄。

He stamped his butt on the floor.
他在地板上踩灭了他的烟蒂。

He was clubbed to death with a butt of a gun.
他是被人用靶垛殴打致死的。

He gave me a butt on the stomach.
他在我腹部撞了一下。

Frieda grinned, pinching him on the butt.
弗里达咧嘴笑了，捏了捏他的屁股。

buttocks是什么意思：
n. 臀部；船尾
v. 背摔

The back section of the buttock on the outside may be sensitive to the touch.
这块肌肉在臀部后面外侧的部分，可以很容易就摸到。

He buttocked his opponent onto the mat.
他把对手背摔在垫子上。

Armor consisting of overlapping plates used to protect the buttocks
护臀甲由相互交迭的甲片构成的铠甲，用来保护臀部

To expose one's buttocks in public as a prank or disrespectful gesture.
露出屁股以戏弄在公共场合暴露自己的屁股，作为一种恶作剧或不尊重的表示

All at once he became conscious of a smart blow upon his buttocks
突然之间，他觉得他的屁股上很疼地挨了一下打。