M3

M3, M-3 or M03 may refer to:

Computing and electronics

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

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

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

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

m³, the cubic metre, a unit of volume
M₃, 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 M₃, an acetylcholine receptor
The M-3 (My Mood Monitor) Screen, a mental health symptom checklist

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

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

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