Home › Words › M › millimetremillimetremillimetre means an SI/MKS unit of measure, the length of ¹⁄₁₀₀₀ of a metre. Symbol: mm.EtymologyFrom French millimètre, equivalent to milli- + metre.nounAn SI/MKS unit of measure, the length of ¹⁄₁₀₀₀ of a metre. Symbol: mme.g.“Holonyms: centimetre < decimetre < metre < kilometre < megametre < gigametre < terametre < petametre”Definitions & examples from Wiktionary (CC BY-SA 3.0).