无穷小量的英文：
dimensionless

Newton says he has abandoned the infinitesimal or infinitely small quantity.
牛顿说他已放弃了微元或无穷小量。

The infinitely small "dx" and "dy" were sometimes described as vanishing or incipient quantities
有时候把无穷小量dx和dy描述成正在消失的或者刚出现的量。

dimensionless quantity
无因次值|无量纲的量

A dimensionless geometric object having no properties except location.
点除了位置没有其它特点的无维几何体

A dimensionless physics is not so profound as it may sound, nor would it necessarily be a terminus of man's downward probing.
无量纲物理学不像听起来那么深奥，也未必是人们向深处探索的终点。

A very useful tool for scale-up is the dimensionless group. This is the grouping of system variables so as to cancel out their dimensions.
在放大中使用的一个很有用的工具是无量纲数群。这是系统变量无因次化的一种组合。