X Definition: A form of signature upon contracts by persons illiterate. X: a mark as a form of signature upon and acceptance of a contract by a person otherwise illiterate or physically unable to sign. Also, an indication of dimensional measurement. In an 1886 Indiana case, Jaqua v Witham & Anderson Co. (106 Ind. 547), at issue was the import of the symbols "3x5" in a lumber dispute. The Court acceptd the evidence in regards to the custom of using X to denote dimensions: "That, by the usages and customs of the dressed lumber trade, the “3x5” ... meant either 3 feet by 5 feet, or 3 inches by 5 inches." Find you are constantly looking up definitions? Try our search provider (works in most modern browsers) If you find an error or omission in Duhaime's Legal Dictionary, or if you have legal term suggestion, we'd love to hear from you!