In military and weaponry

• Webley Mk IV, also known as the "Boer War Model"; .455 caliber British revolver from 1899
• Mark IV tank, an up-armoured variant of the British Mark I tank, 1917.
• Vickers Tank Periscope MK.IV
  Vickers Tank Periscope MK.IV
  The Vickers Tank Periscope MK.IV, invented by Polish engineer Rudolf Gundlach, was first patented in 1936 as Gundlach Peryskop obrotowy. It was the first device to allow the tank commander to have a 360-degree view from his turret, with a single periscope...
  
   (1936); widely used periscope designed in Poland
• Bristol Blenheim Mk.IV; light bomber in Royal Air Force service before and during World War II, the most numerous Blenheim variant
• Mark 4 nuclear bomb
  Mark 4 nuclear bomb
  The Mark 4 nuclear bomb was an American nuclear bomb design produced starting in 1949 and in use until 1953.The Mark 4 was based on the earlier Mark 3 Fat Man design, used in the Trinity test and the bombing of Nagasaki...
  
   (1949–1953); an American nuclear bomb
• Mk IV Turtle helmet (1950s–1980s); British Army standard helmet; a slight design change from the Mk III Turtle helmet
  Mk III Turtle helmet
  The Mk III Helmet was a steel military combat helmet developed for the British Army in 1941. First worn in combat by British and Canadian troops on D-Day, the Mk III was used alongside the Brodie helmet for the remainder of the Second World War...
  
  
• Merkava Mark IV (1999); main battle tank of Israel Defense Forces
• Navy Mark IV (late 1950s–early 1960s); a full pressure suit designed for unpressurized military jets; modified by NASA for Project Mercury astronauts

Other vehicles

• Jaguar Mark IV
  Jaguar Mark IV
  The Jaguar Mark IV is a saloon car built by Jaguar from 1945 to 1949. It was a relaunch of a pre-Second World War model made by SS Cars Ltd from 1936....
  
   (1945–1949), a British saloon car
• Triumph Spitfire
  Triumph Spitfire
  The Triumph Spitfire is a small English two-seat sports car, introduced at the London Motor Show in 1962. The vehicle was based on a design produced for Standard-Triumph in 1957 by Italian designer Giovanni Michelotti...
  
   MKIV (1970–1974), a British sports car
• Lincoln Continental Mark IV
  Lincoln Continental Mark IV
  See Lincoln Mark for a complete overview of the Lincoln Mark Series.The Lincoln Continental Mark IV was a luxury car at the top end of the personal luxury car market sold under the Lincoln brand of the Ford Motor Company in North America between 1972 and 1976. It replaced the successful...
  
   (1972–1976), an American personal luxury car
• British Rail Mark 4
  British Rail Mark 4
  British Rail's fourth design of passenger carriages was designated Mark 4, designed for use in InterCity 225 sets on the newly-electrified East Coast Main Line between London, Leeds, and Edinburgh.-History and construction:...
  
   coaching stock
• Mark 4 (Iarnród Éireann)
  Mark 4 (Iarnród Éireann)
  The CAF Mark 4 are trains operated by Iarnród Éireann in the Republic of Ireland on the InterCity service from Dublin to Cork. These trains have no connection to the BR Mk 4.-Description:...
  
   Irish Rail InterCity train
• Mark IV monorail
  Mark IV monorail
  The Mark IV monorail is a design model of monorail trains. The design was developed by Bob Gurr. Ten were built by Martin Marietta in 1969 at the cost of about six million USD each and they were used on the Walt Disney World Monorail System between 1971 and 1989 before they were replaced by the...
  
  , a design of monorail train used at the Walt Disney World Resort between 1971 and 1989
• Cozy MK IV
  Cozy MK IV
  The Cozy Mark IV is a 4-seat, single engine, homebuilt light aircraft designed by Nat Puffer. The aircraft is built from plans using basic raw materials. It is not a kit aircraft, though many small parts are available prefabricated. The Cozy is similar in design and construction to the 2-seat Rutan...
  
  , an experimental 4 place canard aircraft derived by Nat Puffer from the Burt Rutan Long-EZ

Other technologies

• Canon EOS-1D Mark IV
  Canon EOS-1D Mark IV
  The EOS-1D Mark IV is a professional 16.1 effective megapixels digital single lens reflex camera camera body produced by Canon. The EOS-1D Mark IV is the successor of the Canon EOS-1D Mark III and was announced on October 20, 2009, just four days after Nikon announced the D3s...
  
  , a digital SLR
• Harvard Mark IV
  Harvard Mark IV
  The Harvard Mark IV was an electronic stored-program computer built by Harvard University under the supervision of Howard Aiken for the United States Air Force. The computer was finished being built in 1952. It stayed at Harvard, where the Air Force used it extensively.The Mark IV was all electronic...
  
   (1952), an all-electronic stored-program computer
• MARK-IV %28Software%29, a 1960s-era 4th-generation programming language from Informatics
• Mesa Boogie Mark IV (1993–2008); an electric guitar amplifier designed in Northern California
• Disklavier#Mark IV, a reproducing piano sold by Yamaha Corporation

Other uses

• Mark 4
  Mark 4
  Mark 4 is the fourth chapter of the Gospel of Mark in the New Testament of the Christian Bible. It contains the Parable of the Sower, with its explanation, and the parable of The Mustard Seed...
  
   or Mark IV, the fourth chapter of the Gospel of Mark in the New Testament of the Christian Bible
• The Mark Four
  The Mark Four
  The Mark Four were a pop band from Hertfordshire, England. Members included Kenny Pickett , Eddie Phillips , John Dalton and Jack Jones . The group released four singles, then Dalton left to join The Kinks and Bob Garner replaced him...
  
   (1966–1968); an English band
• MARK IV (Barbershop)
  MARK IV (Barbershop)
  Mark IV is a Barbershop quartet that won the 1969 SPEBSQSA international competition....
  
  ; a barbershop quartet that won the 1969 SPEBSQSA competition
• Emergency Medical Hologram Mark IV, in Star Trek: Voyager, an artificially intelligent medical assistance program