Metre meaning : To measure with a metering device. To imprint a postage mark with a postage meter. To regulate the flow of or to deliver in regulated amounts (usually of fluids but sometimes of other things such as anticipation or breath). The basic unit of length in the International System of Units (SI: Système International d'Unités), equal to the distance travelled by light in a vacuum in 1/299 792 458 seconds. The metre is equal to 39 47/127 (approximately 39.37) imperial inches.