# M3

M3, M-3 or M03 may refer to:

## Computing and electronics

* Apple M3, a central processing unit in the Apple M series
* Intel m3, a brand of microprocessors
* M.3 (aka NF1/NGSFF), a specification for internally mounted expansion cards
* Leica M3, a landmark 35mm rangefinder camera
* Modula-3 (M3), a programming language
* M3, a British peak programme meter standard used for measuring the volume of audio broadcasts
* m3, a macro processor for the AP-3 minicomputer, the predecessor to m4
* M3, a surface-mount version of the 1N4003 general-purpose silicon rectifier diode
* M3 (email client), an unreleased email client for the Vivaldi browser

## Entertainment

* M3, a comic book created by Vicente Alcazar
* M3 adapter, a Game Boy Advance movie player
* M3 (Canadian TV channel), a music and entertainment television channel
* M3 (Hungarian TV channel), a Hungarian television channel
* M3: Malay Mo Ma-develop, a 2010 Philippine TV series
* M3 Music Card, a 2007 flash-based MP3 player
* M3 Perfect, M3 Simply and M3 Real, Nintendo DS and 3DS storage devices
* M3: Sono Kuroki Hagane, a 2014 Japanese anime television series

## Military
### Weapons

* 37 mm Gun M3, a light American anti-tank gun
* M3/M3E1 Multi-role Anti-armor Anti-tank Weapon System (MAAWS) (AKA: Carl Gustaf 8.4cm recoilless rifle), an 84 mm man-portable reloadable anti-tank recoilless rifle
* 90 mm Gun M1/M2/M3, an American anti-aircraft and anti-tank gun
* 105 mm Howitzer M3, an American light artillery piece
* Benelli M3 Super 90, an Italian semi-automatic shotgun
* M3 20mm cannon, a United States development of the Hispano-Suiza HS.404
* M3 fighting knife, a World War II American issue knife
* M3 machine gun, a variant of the M2 Browning
* M3 submachine gun (AKA: Grease Gun), an American submachine gun
* M3 tripod, a modern tripod for the M2 Browning machine gun
* M3, a code name for a United States military mission at Roosevelt Roads Naval Station in Puerto Rico

### Vehicles

* M3 Amphibious Rig, a German self-propelled amphibious bridging vehicle
* M3 Bradley, an American infantry fighting vehicle
* M3 Gun Motor Carriage, American tank destroyer
* M3 half-track, an armored military vehicle
* M3 Lee, an American medium tank; also known as "M3 Grant" in Commonwealth service
* Panhard M3 PTT, a French armored personnel carrier
* HMS Raglan (M3), a WWI British Royal Navy monitor
* M3 Ram, a Canadian cruiser tank
* M3 Scout Car, an American armored vehicle
* M3 Stuart, an American light tank
* HSwMS Visborg (M03), a Swedish Royal Navy mine layer
* HSwMS M3, a Swedish Navy mine sweeper (1940–1955)
* HMS M3, a British Royal Navy minelayer submarine of the post-WWI period

## Music

* Major third (M3), a type of musical interval
* Major thirds tuning (M3 tuning), a regular tuning with major-third intervals between successive strings
* Minor third (m3), a type of musical interval
* M3 (album), a 1999 album by Mushroomhead
* M3 (band), an American rock band
* M3 Classic Whitesnake, a band featuring Bernie Marsden, Micky Moody and Neil Murray
* M3 Records, a record label
* Korg M3, a workstation synthesizer

## Science and medicine

* m$^3$, the cubic metre, a unit of volume
* M$_3$, the minimal modular, but non-distributive lattice in mathematical order theory
* ATC code M03, Muscle relaxants, a subgroup of the Anatomical Therapeutic Chemical Classification System
* Messier 3 (M3), a globular cluster in the constellation Canes Venatici
* Muscarinic acetylcholine receptor M$_3$, an acetylcholine receptor
* The M-3 (My Mood Monitor) Screen, a mental health symptom checklist

## Transport
### Air transport

* ABSA - Aerolinhas Brasileiras IATA airline designator M3, a cargo airline based in Campinas, Brazil
* Miles M.3 Falcon, a 1930s British four-seat cabin monoplane

### Automobiles

* Bisu M3, a Chinese MPV
* BMW M3, a German compact performance car series
* BYD M3, a Chinese MPV
* Dongfeng Fengxing Lingzhi M3, a Chinese MPV
* Haima M3, a Chinese subcompact sedan
* JAC Refine M3, a Chinese MPV

### Roads and routes

* Eastern Freeway (Melbourne), part of the M3 in Victoria, Australia
* EastLink (Melbourne), part of the M3 in Victoria, Australia
* Highway M03 (Ukraine), an international highway connecting Kyiv with Dovzhansky
* M3 highway (Russia), another name for the Ukraine Highway in Russia
* M-3 (Michigan highway), a state highway in the Detroit metropolitan area
* M3 motorway (disambiguation), several roads
* M3 (New York City bus), a New York City Bus route in Manhattan
* M3 Milton–City Centre, a bus route in Glasgow
* M3 (East London), a Metropolitan Route in East London, South Africa
* M3 (Cape Town), a Metropolitan Route in Cape Town, South Africa
* M3 (Pretoria), a Metropolitan Route in Pretoria, South Africa
* M3 (Port Elizabeth), a Metropolitan Route in Port Elizabeth, South Africa
* Route M-3 (MTA Maryland), a former bus route in Baltimore, Maryland
* Jalan Datuk Wira Poh Ah Tiam, numbered M3 in Malacca, Malaysia
* M3 road (Zambia), a road in Zambia
* M3 road (Malawi), a road in Malawi

### Rail transport

* LCDR M3 class, a steam locomotive class of the London, Chatham & Dover Railway
* M1/M3 (railcar), a Long Island Rail Road and Metro-North Railroad railcar
* Sri Lanka Railways M3, a diesel-electric locomotive class of Sri Lanka Railways
* Line M3 (Budapest Metro), the North-South Line of the Budapest Metro, Hungary
* M3 (Copenhagen) (City Circle Line or Cityringen), a future expansion of the Copenhagen Metro
* M3 (Istanbul Metro), a rapid transit line in the European part of Istanbul, Turkey
* Milan Metro Line 3, a subway line serving Milan, Italy

## Other uses

* M3, an ISO metric screw thread size
* M3 (economics), a measure of the money supply
* M3 (hieroglyph), the Ancient Egyptian baker's tool hieroglyph
* MLBB M3 World Championship, the third esports world championship for the mobile game Mobile Legends: Bang Bang held in 2021
* M3, a difficulty grade in mixed climbing