Mils

Part of speech: noun

Definitions

1. A unit of measurement equal to one-thousandth of an inch, often used in engineering and manufacturing contexts
2. A term referring to a thousand units of currency in some countries, particularly in the context of pricing
3. A colloquial expression for a very small amount or quantity, emphasizing minuteness or insignificance

Etymology: The word "mils" is simply the plural of "mil," and the phrase it belongs to is colloquial: "not one mil" or "a mil" means a tiny amount, the sort of minuteness that the metric and engineering senses would never suggest. The "mil" itself comes from the Latin "mille," meaning "thousand," and it reached English as a clipping of the metric prefix "milli-," which multiplies a unit by one thousandth. A millimetre is a thousandth of a metre, and a millilitre is a thousandth of a litre, so the short form carried that sense of "thousandth" with it. Because the clipped form was borrowed from these longer scientific words, "mil" first appeared as a unit name rather than as slang. Engineers and measurers use it for a thousandth of an inch, a convenient size for wire gauges and sheet thicknesses, and a milliradian, a thousandth of a radian, follows the same pattern. The informal sense of a negligible quantity grew out of the technical one: a thing measured in thousandths is, by ordinary standards, hardly there at all.

Synonyms: thousandths of an inch, thousands