millesimal

Millesimal refers to a unit of measurement or a system based on thousandths. It is derived from the Latin word "millesimus," meaning "thousandth." In practical terms, a millesimal part is one-thousandth of a whole. This concept is encountered in various contexts, though the term itself is not as common as prefixes like "milli-" which also denotes thousandths.

One notable application of the millesimal concept is in the measurement of angles. A millesimal system for angles divides a circle into 6400 units, with each unit representing 1/6400th of a circle. This system is often used in artillery, surveying, and navigation due to its precision and ease of calculation. In this context, "millesimal" refers to these subdivisions.

Beyond angular measurement, the term can also appear in specific scientific or technical fields where a thousandth of a particular quantity is a relevant unit. For instance, in some pharmaceutical or chemical contexts, concentrations might be expressed in millesimal terms. However, the more common practice is to use the prefix "milli-" such as milligrams (mg) or milliliters (mL) to denote thousandths of a gram or liter, respectively. The millesimal concept, therefore, generally signifies a division into one thousand equal parts.