梯级的英文：
rundle
stave
tread

参考例句：

As dorian hurried up its three rickety steps, the heavy odour of opium met him.
道林快步走上那三级不住晃动的梯级时，闻到了浓重的鸦片烟味。

A step in a straight stairway.
(平行)梯级一段直楼梯中的一级

Cut-in index: Divisions cut into edge of book to indicate alphabetical steps. Also called Step index.
梯级形索引:书本切口旁边，顺着字节次序切成梯级形状。

We also talk of individual steps which make up a staircase or a flight of steps steps
还可用以指构成楼梯或一段台阶的梯级

Dots on the three lowest rungs would indicate that the system possesses no internal energy
圆点在三个最低梯级上，就表示这个系统没有内能。

Finally, envision yourself climbing the ladder and writing down the pairs of letters that make up each rung.
最后，想像自己正在爬梯子，将构成每对字母的梯级写下来。

The elder brother never gained a stave, or raised his foot to mount one.
哥哥从来没有上升到上面的一个梯级或者抬起脚来攀登一下。

After processing, the sensitometrically exposed step wedge is read on a densitometer and the data is plotted
加工完毕后，即用密度计对试验胶上复制的阶梯级谱的密度进行测定，然后用测得的数据作图。

An often portable structure consisting of two long sides crossed by parallel rungs, used to climb up and down.
梯子一种通常是可移动的结构物，由长长的两边和两边平行的梯级连接组成，用于爬上爬下

rundle是什么意思：
n. 梯级
stave是什么意思：
n. 狭板；棍，棒；梯级；诗句；五线谱表
v. 压扁；破碎；击穿；穿孔；延缓

A barrel stave.
桶板

cask stave broken
桶板破裂

The side of the boat was staved in by the collision.
船侧撞穿了。

tread是什么意思：
n. 踏，踩，走；步态；踏板；胎面；鞋底
v. 踏，踩，走

Tread on a worm and it will turn
困兽犹斗

They have caterpillar treads or tracks on the wheels.
它们的车轮上有履带胎面或轨道。

To crush,grind,or tread noisily.
嘎吱嘎吱地压，嘎吱嘎吱地碾，嘎吱嘎吱地跺