A gang sign.

(idiomatic) Something that is symbolic of an era.

A signal that only takes discrete values (contrasted to an analog signal that can take continuously varying values).

A signal that can vary in a continuous manner (as opposed to a digital signal that only takes discrete values).

(electrical engineering) The ratio comparing signal power to noise power. / (by extension) The quantity of quality information compared to irrelevant or incorrect information.

A form of entry at the customhouse, by which goods, respecting which the importer is not possessed of full information, may be provisionally landed for examination.

(statistics) A measure of how likely it is to draw a false conclusion in a statistical test, when the results are really just random variations.

(statistics) A measure of how unlikely it is that a result has occurred by chance.

To sign again; to provide one's signature again. / (by extension) To sign a contract renewing or restarting a professional relationship, such as that of a professional athlete with a sports team.

Alternative form of at sign