国こく際さい単たん位い系けい

noun

International System of Units; SI

Technical term for the modern metric system of measurement; often abbreviated as SI.

See also: ＳＩ

• 国こく際さい単たん位い系けいでは、長ながさの基き本ほん単たん位いはメートルです。

  In the International System of Units, the base unit of length is the meter.