(topology) Such that its topology has a countable base, said of a topological space.

(computer security) A security vulnerability in a computer system.

plural of secondary amine

A system of units used in physics and other sciences, often abbreviated as mks. It is the basis of the SI system of international units.

(sciences) A system of units formerly used in physics (now replaced by the SI system), in which the basic units of length, mass and time were respectively centimeter, gram, and second.

Information that is widely known, but not acknowledged openly. / (dated) Information that is not widely known, despite being freely available.

(Christianity) The prophesied return of Jesus Christ.

(US) A nine-digit number issued to citizens, permanent residents, and temporary (working) residents under section 205(c)(2) of the Social Security Act, codified as 42 U.S.C. § 405(c)(2). The number is issued to an individual by the Social Security Administration. Its primary purpose is to track individuals for taxation purposes. Abbreviated as SSN. In recent years the SSN has become a de facto national identification number.

(law, chiefly US, Canada) The criminal offence of murder in a form defined as less serious than first-degree murder; the precise distinction may vary by jurisdiction but typically involves second-degree murder being intentional but not premeditated.

A sheet of paper on which a carbon copy is made.