A Middle English variant of sine.n. A Japanese copper or bronze coin, equal to the one-hundredth part of a yen or dollar; a Japanese cent. One- and two-sen copper pieces and five-, ten-, twenty-, and fifty-sen silver pieces are in circulation.n. An abbreviation of senior.n. The name given in Hindustan to a unit of weight equal to one kilogramn. to a unit of volume equal to the liter. These units and their multiples were legalized in 1871, mainly for use by the railways.n. An abbreviation of Senate or Senator.