Optics and photography Stop, the difference of a power of 2 in the context of exposure value F-stops, a unit of measure of aperture Stop bath, a chemical used in film processing Arrestation devices Door stop Petzl Stop, a descender used in caving Train stop, a train protection device Halting Stop sign, a traffic signal Full stop (full point, period), a punctuation mark STOP, used to replace that symbol in telegraphs, as Morse code has no method to produce it (sometimes STOP was used for a comma and FULL STOP for the period). Stop error, a computer error screen Terry stop, a brief police detention in the United States Other uses Safe Tables Our Priority, a food safety organization Secure Trusted Operating Program, a computer operating system Stop, a futuristic display typeface by Aldo Novarese Stop squark, in quantum physics, a supersymmetric squark which is the superpartner of the top quark Society of Teachers Opposed to Physical Punishment, an organisation based in the United Kingdom Strategic Operations, a military, police, and medical training company in San Diego Stop or stopper, a specific type of card holding in one suit in the game of contract bridge (see: Glossary of contract bridge terms#stopper) See also Stopper (disambiguation) Halt (disambiguation)