DK2 6 in. 14 HP Gas Powered Kohler Engine Certified Commercial Chipper Shredder with Extended Axles and Trailer Tow Hitch

Fourteen or 14 may refer to:

• 14 (number), the natural number following 13 and preceding 15
• one of the years 14 BC, AD 14, 1914, 2014

6 (six) is the natural number following 5 and preceding 7. It is a composite number and the smallest perfect number.

Commercial may refer to:

• (adjective for) commerce, a system of voluntary exchange of products and services
  • (adjective for) trade, the trading of something of economic value such as goods, services, information or money
• a dose of advertising conveyed through media (such as radio or television)
  • Radio advertisement
  • Television advertisement
• Two functional constituencies in elections for the Legislative Council of Hong Kong:
  • Commercial (First)
  • Commercial (Second)
• Commercial (album), a 2009 album by Los Amigos Invisibles
• Commercial broadcasting
• Commercial style or early Chicago school, an American architectural style
• Commercial Drive, Vancouver, a road in Vancouver, British Columbia, Canada
• Commercial Township, New Jersey, in Cumberland County, New Jersey

DK2 may refer to:

• Batman: The Dark Knight Strikes Again
• Dungeon Keeper 2
• Donkey Kong 2
• Oculus Rift Developer kit 2
• Droga krajowa 2, a national road in Poland

An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy.

Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power generation), heat energy (e.g. geothermal), chemical energy, electric potential and nuclear energy (from nuclear fission or nuclear fusion). Many of these processes generate heat as an intermediate energy form; thus heat engines have special importance. Some natural processes, such as atmospheric convection cells convert environmental heat into motion (e.g. in the form of rising air currents). Mechanical energy is of particular importance in transportation, but also plays a role in many industrial processes such as cutting, grinding, crushing, and mixing.

Mechanical heat engines convert heat into work via various thermodynamic processes. The internal combustion engine is perhaps the most common example of a mechanical heat engine in which heat from the combustion of a fuel causes rapid pressurisation of the gaseous combustion products in the combustion chamber, causing them to expand and drive a piston, which turns a crankshaft. Unlike internal combustion engines, a reaction engine (such as a jet engine) produces thrust by expelling reaction mass, in accordance with Newton's third law of motion.

Apart from heat engines, electric motors convert electrical energy into mechanical motion, pneumatic motors use compressed air, and clockwork motors in wind-up toys use elastic energy. In biological systems, molecular motors, like myosins in muscles, use chemical energy to create forces and ultimately motion (a chemical engine, but not a heat engine).

Chemical heat engines which employ air (ambient atmospheric gas) as a part of the fuel reaction are regarded as airbreathing engines. Chemical heat engines designed to operate outside of Earth's atmosphere (e.g. rockets, deeply submerged submarines) need to carry an additional fuel component called the oxidizer (although there exist super-oxidizers suitable for use in rockets, such as fluorine, a more powerful oxidant than oxygen itself); or the application needs to obtain heat by non-chemical means, such as by means of nuclear reactions.

Gas is one of the four fundamental states of matter. The others are solid, liquid, and plasma. A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or compound molecules made from a variety of atoms (e.g. carbon dioxide). A gas mixture, such as air, contains a variety of pure gases. What distinguishes gases from liquids and solids is the vast separation of the individual gas particles. This separation usually makes a colorless gas invisible to the human observer.

The gaseous state of matter occurs between the liquid and plasma states, the latter of which provides the upper-temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention. High-density atomic gases super-cooled to very low temperatures are classified by their statistical behavior as either Bose gases or Fermi gases. For a comprehensive listing of these exotic states of matter, see list of states of matter.

Kohler is an occupational surname of German origin. It means "charcoal burner". Notable people with the surname include:

• Alan Kohler, Australian journalist
• Anton Kohler, German chess player
• Berthold Kohler (born 1961), German journalist
• Charles-Amédée Kohler (1790–1874), Swiss chocolate maker
• Ernesto Kohler (1849–1907), flautist and composer
• Fred Kohler, American actor
• Josef Kohler, German jurist
• Juliane Köhler, German actress
• Jürgen Kohler, former German football player
• Kaufmann Kohler (1843–1926), Reform rabbi
• Klaus J. Kohler, German phonetician
• Max J. Kohler, American lawyer
• Richie Kohler, shipwreck diver and historian
• Robert E. Kohler (born 1937), American chemist and historian of science
• Sheila Kohler, South African writer

With or WITH may refer to:

• With, a preposition in English
• Carl Johannes With (1877–1923), Danish doctor and arachnologist
• With (character), a character in D. N. Angel
• With (novel), a novel by Donald Harrington
• With (album), a 2014 album by TVXQ
• With (EP), a 2021 EP by Nam Woo-hyun