The meaning of "M1" on a keyboard can vary depending on the type of keyboard. Here are some possible meanings:

• On the GK61v2 keyboard, "M1" may refer to the left mouse button, according to a Reddit post.
• On the Cooler Master MK850 keyboard, "M1" is one of five pre-installed profile modes that correspond to specific use cases. In this case, "M1" refers to Normal Keyboard Mode with no Aimpad enabled.
• On the Logitech G105 Gaming Keyboard, "M1" is one of three M-keys that extend the capability of the G-keys, allowing you to assign up to three different key configurations to each profile for your G-keys. This allows you to react to different game scenarios in a single profile by switching between the M1, M2, and M3 keys. According to a Super User post, the MR-key is used to record quick macros.
• In an Apple patent for a design for a Mac in a keyboard, "M1" refers to a key on the keyboard.
• In the game Skyrim, "M1" and "M2" refer to the left and right mouse buttons, respectively, according to a post on the Gamesas forum.
• On the SteelSeries Apex Pro Full-Size Wired Mechanical Omnipoint Adjustable Actuation Switch Gaming Keyboard, "M1" is one of several macro keys that can be customized with SteelSeries software.

In summary, "M1" on a keyboard can refer to a variety of things, including a mouse button, a pre-installed profile mode, a key for assigning key configurations, a key on a keyboard patent, a mouse button in a game, or a macro key.