M42 or M-42 may refer to: In science: *

Messier 42 Messier may refer to: People with the surname *Charles Messier, French astronomer *Éric Messier, former NHL defenseman *George Messier, French inventor *Jean-Marie Messier, former CEO of Vivendi Universal *Marc Messier, Canadian actor from Quebec ...

, a nebula also called the Orion Nebula * the 42nd Mersenne prime, 2^25964951-1, discovered in 2005 *an Y-chromosomal mutation, see Haplogroup B-M42 In transportation: *

M42 motorway The M42 motorway runs north east from Bromsgrove in Worcestershire to just south west of Ashby-de-la-Zouch in Leicestershire, passing Redditch, Solihull, the National Exhibition Centre (NEC) and Tamworth on the way, serving the east of the Bi ...

, a motorway in the United Kingdom * M-42 (Michigan highway), a state highway in Michigan * M42 (Cape Town), a Metropolitan Route in Cape Town, South Africa * M42 (Pretoria), a Metropolitan Route in Pretoria, South Africa *

M42 (New York City bus) Several companies, most prominently the Metropolitan Transportation Authority (MTA), operate a number of bus routes in Manhattan, New York (state), New York, United States. Many of them are the direct descendants of streetcar lines (see list of ...

, a New York City Bus route in Manhattan * BMW M42, a 1989 automobile piston engine * Dodge M42, ¾-ton command truck, 1950s *

M42 (sub-basement) M42 is a sub-basement of Grand Central Terminal in Midtown Manhattan, New York City. The basement contains an electrical substation that provides electricity to the terminal and helps power its tracks' third rails. The facility opened in 1918 ...

, a power station at New York City's Grand Central Terminal In photography: * M42 lens mount, a standard for cameras In firearms and military equipment: *

Ag m/42 A&G, AG, Ag or ag may refer to Businesses and organizations * A&G Railroad (former reporting mark AG) * Action Group (Nigeria), a political party during the Nigerian First Republic * Aktiengesellschaft, a German type of corporation * Assembl ...

, a Swedish semi-automatic rifle which saw limited use by the Swedish Army from 1942 until the 1960s * M42 Duster, a United States Army self-propelled anti-aircraft gun *

M42 (gas mask) The M40 field protective mask was one of various protective masks used by the United States Armed Forces and its allies to protect from field concentrations of chemical and biological agents, along with radiological fallout particles. It is no ...

, a United States military gas mask *

M/42 (bicycle) Swedish military bicycles ( sv, militärcykel), or Swedish army bicycles, have been used in the Swedish military for over a century. History The first bicycles in the Swedish military were privately owned or bought for testing purposes. Bicyc ...

, a Swedish military bicycle *

45 mm anti-tank gun M1942 (M-42) The M-42 was a 45-mm Soviet Union, Soviet light semi-automatic anti-tank gun. Its full official name is 45-mm anti-tank gun model 1942 (M-42) (Russian: 45-мм противотанковая пушка образца 1942 года (М-42)). These ...

, a Soviet anti-tank gun (Motovilikha Plants) *

Duperite M42 helmet The M42 Duperite helmet was a paratrooper helmet issued to Australian paratroopers during WW2 and was produced by The Australian Moulding Corporation. The helmet got its eponymous name from the shock impact-absorbing material it was compose ...

, an Australian WWII helmet * M42

Stahlhelm The ''Stahlhelm'' () is a German military steel combat helmet intended to provide protection against shrapnel and fragments of grenades. The term ''Stahlhelm'' refers both to a generic steel helmet and more specifically to the distinctive Ger ...

, a type of German WWII helmet * M42, a Smith & Wesson hammerless revolver *

M42 United Defense The United Defense M42, sometimes known as the Marlin for the company that did the actual manufacturing, was an American submachine gun used during World War II. It was produced from 1942 to 1943 by United Defense Supply Corp. for possible issue a ...

submachine gun, an American weapon used in World War II * M42 command truck In manufacturing: * M42 is the Unified numbering system code ("miscellaneous nonferrous metals and alloys") for a grade of high-speed steel with cobalt

See also