J4/J04, J-4/J-04 or J.4/J.04 may refer to: In science and academia * ATC code J04 Antimycobacterials, a subgroup of the Anatomical Therapeutic Chemical Classification System * Janko group J4, in mathematics * S/2003 J 4, a natural satellite of Jupiter * J04 : acute laryngitis and tracheitis ICD-10 code * Square cupola, Johnson Solid number 4In military * Mikoyan-Gurevich MiG-15, Chinese designation of this Soviet-made aircraft is J-4 * HMAS J4, an Australian Royal Navy submarine which saw service during World War I * Junkers J 4, a 1917 German sesquiplane format warplane * J4F was the U.S. Navy's designation for the Grumman Widgeon seaplane.In transportation * Airmak J4, an Italian microlight aircraft design * Auster J-4, a 1946 British single-engined two-seat high-wing touring