(sports, snowboarding, skiing) Clipping of 900. (900° spin)

The date of the attack on the Twin Towers and the Pentagon in the USA, September 11th, 2001. / (metonymically) The attack itself.

An event comparable to 9/11.

A day job, especially at a large company, emphasizing banality. / The workday itself (the period of the day between 9 am and 5 pm). / One who works in a job from 9 am to 5 pm.

(physics) The only stable isotope of beryllium, ⁹₄Be, having four protons and five neutrons

Initialism of carbohydrate antigen 19-9, a tumor marker for colon and pancreatic cancer also found in non-malignant conditions.

Alternative spelling of K9.

plural of 9/11

Alternative spelling of nine-tenths

Alternative form of cloud nine