International Standard Serial Number International Standard Serial Number An International Standard Serial Number (ISSN) is an eight-digit serial number used to uniquely identify a serial publication. The ISSN is especially helpful in distinguishing between serials with the same title. ISSN are used in ordering, cataloging, interlibrary loans, and other practices in connection with serial literature. The ISSN system was first drafted as an International Organization for Standardization (ISO) international standard in 1971 and published as ISO 3297 in 1975. ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard. When a serial with the same content is published in more than one media
Opposite Day that it is an opposite day. Opposite Day "'Opposite Day" Opposite Day is sometimes declared retroactively to indicate that something which has just been said now has the opposite of its original meaning (similar to the practice of crossed fingers to automatically nullify promises). The game has also been compared to a children's "philosophy course." Opposite day causes a self referential paradox. On opposite day, it could be said that "Today is opposite day." Therefore, it is not opposite day, but if you say it is a normal day it would be considered a normal day, which contradicts the fact