Simplex may refer to:

Biology List of species named simplex, a common species name Herpes simplex, a viral disease caused by Herpes simplex viruses

Companies and branded products Simplex (bicycle), a French bicycle derailleur brand Simplex Manufacturing Corporation, an American manufacturer of motorcycles in Louisiana from 1935 to 1975 American Simplex, an American automobile made in Mishawaka, Indiana, US Simplex Automobile Company, a defunct luxury car manufacturer from 1907 to 1921 Crane-Simplex, a defunct luxury car manufacturer in New York, US at the start of the 20th century Sheffield-Simplex, a British vehicle manufacturer operating 1907–1920 Bergmann Simplex, an early 20th-century, German-made handgun Mercedes Simplex, an automobile model produced between 1902 and 1909 Simplex Typewriter Company, an index typewriter manufacturer A trade name used by British railway locomotive manufacturers The Motor Rail & Tramcar Co Ltd The trade name of the swinging-tray record changer used in Wurlitzer jukeboxes from the 1930s to the 1950s A brand of fire alarm systems made by SimplexGrinnell A manufacturer of jacks used in railroads and mining industries, now owned by Actuant Corporation

Linguistics A monomorphemic form of a word that is not a part of a compound or derivational affixes

Mathematics Simplex, a term in geometry meaning an n-dimensional analogue of a triangle Simplicial polytope, a polytope with all simplex facets Simplicial complex, a collection of simplicies Pascal's simplex, a version of Pascal's triangle of more than three dimensions Simplex algorithm, a popular algorithm for numerical solution of linear programming problems Simplex graph, derived from the cliques of another graph Simplex noise, a method for constructing an n-dimensional noise function Simplex plot, a ternary plot used in game theory

Technology

Simplex communication, a one-way communications channel Simplex signaling, signalling in which two conductors are used for a single channel Simplex, using a single frequency for transmit and receive instead of an amateur radio repeater SimpleX Chat, a privacy focused messaging application Simplex printing, printing one sided pages, a technique that is contrast to duplex printing Small Innovative Missions for Planetary Exploration (SIMPLEx) program at NASA