A sign is an entity which indicates another entity. Sign may also refer to:

Communication

Signage Signage is the design or use of signs and symbols to communicate a message. A signage also means signs ''collectively'' or being considered as a group. The term ''signage'' is documented to have been popularized in 1975 to 1980. Signs are any ...

, the use of signs and visual graphics to convey information *

Signature A signature (; from la, signare, "to sign") is a handwritten (and often stylized) depiction of someone's name, nickname, or even a simple "X" or other mark that a person writes on documents as a proof of identity and intent. The writer of a ...

, a handwritten depiction of someone's name or other mark used as a proof of identity and intent *

Sign (semiotics) In semiotics, a sign is anything that communicates a meaning that is not the sign itself to the interpreter of the sign. The meaning can be intentional, as when a word is uttered with a specific meaning, or unintentional, as when a symptom is t ...

, anything that communicates a meaning *

Sign language Sign languages (also known as signed languages) are languages that use the visual-manual modality to convey meaning, instead of spoken words. Sign languages are expressed through manual articulation in combination with non-manual markers. Sign l ...

, a languages that uses the visual-manual modality to convey meaning

Mathematics

Sign (mathematics) In mathematics, the sign of a real number is its property of being either positive, negative, or zero. Depending on local conventions, zero may be considered as being neither positive nor negative (having no sign or a unique third sign), or it ...

, an indication of negative and positive numbers ** Sign function, also known as the signum function **

Sign of a permutation In mathematics, when ''X'' is a finite set with at least two elements, the permutations of ''X'' (i.e. the bijective functions from ''X'' to ''X'') fall into two classes of equal size: the even permutations and the odd permutations. If any total ...

of a finite set

Organizations

Project Sign Project Sign (Project Saucer) was an official U.S. government study of unidentified flying objects (UFOs) undertaken by the United States Air Force (USAF) and active for most of 1948. It was the precursor to Project Grudge. History The project w ...

, a project by the U.S. Air Force to investigate unidentified flying objects (UFOs) * ''Servicio de Inteligencia de la Gendarmería Nacional'' or '' Inteligencia de la Gendarmería Nacional Argentina'', the Argentine intelligence service *

Scottish Intercollegiate Guideline Network Healthcare Improvement Scotland (HIS) is the national healthcare improvement organisation for Scotland. It is a public body which is part of the Scottish National Health Service, created in April 2011. History NHS Quality Improvement Scotland ( ...

, a Scottish group that develops evidence-based medical guidelines

Music

* Sign (band), an Icelandic band * ''Sign'' (Clock DVA album), 1993 * "Sign" (Mr. Children song), 2004 * "Sign" (Beni Arashiro song), 2010 * "Sign" (Flow song), 2010 * "Sign", a 2018 song by Exo from

Don't Mess Up My Tempo ''Don't Mess Up My Tempo'' (stylized in all caps) is the fifth studio album by South Korean–Chinese boy band Exo. It was released on November 2, 2018 by SM Entertainment. Member Lay is featured in the Chinese version of lead track, "Tempo", mar ...

* "Sign", a 2001 song by Marcella Detroit from '' Dancing Madly Sideways'' * "Sign", a song by Susumu Hirasawa ** "Sign-2", a different version of "Sign" from '' Berserk: Millennium Falcon Hen Seima Senki no Shō'' * ''Sign'' (Autechre album), 2020 * "The Sign" (song), a 1993 song by Ace of Base * ''The Sign'' (Ace of Base album), a 1993 album by Ace of Base

Surname

* Christopher Sign (19762021), American journalist

Other uses

Astrological sign In Western astrology, astrological signs are the twelve 30-degree sectors that make up Earth's 360-degree orbit around the Sun. The signs enumerate from the first day of spring, known as the First Point of Aries, which is the vernal equinox. ...

, one of twelve sectors of the sky in astrology *

Medical sign Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showi ...