(Internet slang) Censored spelling of ass.

(physics) The only stable isotope of manganese, ⁵⁵₂₅Mn, having 25 protons and 30 neutrons

(Canada, US, fiction) Pertaining to a fake telephone number. The local exchange and area code number 555 was reserved in North American dialing plan for fictional numbers, prior to the 21st century.

Of telephone numbers dialed in North America, widely used for fictional numbers in television shows, films, and other media.