M8

M8 or M-8 may refer to:

In aviation:
* Loening M-8, a 1910s American fighter monoplane
* Miles M.8 Peregrine, a 1930s British twin-engined light transport monoplane

In computers:
* M8 (cipher), an encryption algorithm

In engineering:
* a standard bolt and nut size in the metric system. See ISO metric screw thread.

In entertainment:
* M8 (magazine), a dance music magazine based in Scotland
* Media 8 Entertainment (M8 Entertainment), a film company

In electronics:
* Leica M8, a digital Leica rangefinder camera
* M8 miniOne, a smartphone designed by Meizu similar to the iPhoneIn science:
* Messier 8 (M8), a nebula also referred to as the Lagoon Nebula

In firearms and military equipment:
* M8, an alternate designation for the XM8 rifle, a lightweight assault rifle
* M-8 rocket, a variant of the RS-82 rocket used by the Soviet Union in World War II
* M8 Greyhound, an American armored car used during World War II
* M8-AGS, a US Army light tank cancelled in 1996
* Howitzer Motor Carriage M8, an American self-propelled howitzer vehicle developed during World War II

In transportation:
* M8 motorway, a motorway in Scotland
* Russian route M8 is another name for the Kholmogory Highway in Russia
* M8 Motorway, the soon-to-be major interurban motorway connecting Cork and Dublin in the Republic of Ireland. As the M8 is built, it replaces the N8 road.
* M-8 (Michigan highway) a state highway in Detroit also known as the Davison Freeway
* M8 (railcar), a new railcar being designed for the Metro-North Railroad in New York
* Western Freeway in Victoria, Australia, designated "M8"

In slang:
* M8, internet slang for "mate"