The word "micrometer" is a neoclassical coinage . The "Merriam-Webster Collegiate Dictionary" says that English got it from French and that its first known appearance in English writing was in 1670. Neither the metre nor the micrometre (μm) nor the micrometer (device) as we know them today existed at that time. However, the people of that time did have much need for, and interest in, the ability to measure small things and small differences. The word was no doubt coined in reference to this endeavor, even if it did not refer specifically to its present-day senses.