Pronunciation: [mˈɪlɪmˌa͡ɪkɹɒn] (IPA) 
The spelling of the word "millimicron" can be a source of confusion. It is pronounced /ˈmɪlɪˌmaɪkrɒn/ with a stress on the second syllable. The word refers to a unit of length equal to one thousandth of a micron or one billionth of a meter. The reason for the double "m" in millimicron is to avoid confusion with the similar-sounding word "micron", which can also be spelled as "mike-ron", but refers to a different measurement.
Micromillimeter (1).
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "millimicron" is derived from combining two different units of measurement: "milli-" and "micron".
- "Milli-" is a prefix denoting one thousandth of a unit, derived from the Latin word "mille" meaning "thousand".
- "Micron" is a unit of length equal to one-millionth of a meter, derived from the Greek word "mikros" meaning "small".
The combination of these two terms creates "millimicron", which represents one thousandth (milli) of a millionth (micron) of a meter.
