A cog is a tooth of a gear or cogwheel or the gear itself.
Cog, COG, CoG, or The Cog may also refer to:
Science and engineering Rear sprocket of a bicycle Cog (ship), a type of sailboat from the 10th century onward Center of gravity, a spatial point related to an object's center of mass Cluster of Orthologous Groups of proteins; see Sequence homology and MicrobesOnline Conserved oligomeric Golgi complex, that includes COG2, COG4, etc. INSEE code (also code officiel géographique), a numerical indexing code used by the French National Institute for Statistics and Economic Studies Mount Washington Cog Railway, the world's first mountain-climbing cog railway OpenCog, a project that aims to build an open source artificial general intelligence framework Chip on Glass; see Liquid-crystal display
Entertainment and media C.O.G., a 2013 American drama C.O.G. (2025 film), an American science fiction horror film "The Changing of the Guard" (The Twilight Zone), a 1962 episode of the TV series The Twilight Zone "Cog" (advertisement), a British television and cinema advertisement launched by Honda Star Wars Jedi Quest 8: The Changing of the Guard, the eighth book in the Star Wars Jedi Quest series by Jude Watson COG, a 2020 novel by Greg van Eekhout "C.O.G." (2025 film), film directed by Tommy Savas
Fictional characters Coalition of Ordered Governments, a fictional organization from the Gears of War series Cogs, the fictional antagonists in the MMORPG Toontown Online Cogs, the fictional foot soldiers of Power Rangers Machine Empire Cog (comics), a character from the Spawn comics
Music Cog (band), an Australian progressive rock band "Changing of the Guards", a single from Bob Dylan's 1978 album Street-Legal The Changing of the Guard (album), 2010 album by indie rock band Starflyer 59 "Change of the Guard", a song from Steely Dan's 1972 album Can't Buy a Thrill "Changing of the Guard", a song from Exodus' 1990 album Impact Is Imminent
Organizations Canberra Ornithologists Group, an Australian ornithological organization Children's Oncology Group, a National Cancer Institute supported clinical trials group Church of God (disambiguation), a name used by numerous, mostly unrelated Christian denominational bodies Council of Government (disambiguation), various government bodies Council of governments, regional bodies that exist throughout the United States Covenant of the Goddess, a cross-traditional Wiccan group The ISO 3166-1 alpha-3 country code for Republic of the Congo
Other uses Cog (software), an open source audio player for macOS Cog (project), a project at the Humanoid Robotics Group of the Massachusetts Institute of Technology Continuity of government, defined procedures that allow a government to continue its essential operations in case of catastrophe Changing of the Guard (or Guard Mounting), a formal ceremony in which sentries are relieved by their replacements Course over ground, the actual path followed by a vessel from A to B as determined by its course
See also Change of gauge (disambiguation), with various senses in the airline and rail industries C0G, an EIA Class 1 dielectric material with the lowest capacitance/temperature dependence CoG (disambiguation) COGS (disambiguation) Coq, in computer science, was the ancient name of Rocq, an interactive theorem prover Kog (disambiguation) System Settings, an application included with macOS Settings (Windows), a component of Microsoft Windows