millimeter

A micrometer is one thousandth of one millimeter..一微米是一毫米的千分之一。

We're also good at seeing big clouds of small particles of dust. ... But in between dust grains up to a millimeter in size and the smallest planets we can see, we're blind..我们也同样擅长于发现那些一大堆的尘埃...但是如果要去发现那些毫米级的尘埃，和那些我们能看到的最小的行星，我们几乎就成了盲人。

On average these mosses grow at the glacial speed of 1 millimeter per year—and some of the turfs are meters thick..平均来说，这些苔藓以每年大约1毫米的极慢速度生长，而某些草皮有数米厚。

millimeter wave,毫米波

square millimeter,平方毫米