Keycode: The output after you press a keyswitch. For example, "Q" or "F11".
Keymap: Also called keyboard layout. Examples of keymaps include QWERTY, DVORAK, Colemak.
Layers: Layers are a QMK specific functionality. The concept is similar to a Fn or FnLock key that is seen on some keyboards.
Layer Key: The keycode you use to switch to a different layer. If you are using QMK Configurator, you'll see M(0) or M(1). If you are following 4. Customizing Keyboard Layout for Linux with QMK, you'll see the RAISE and LOWER layer keys in the default dactyl_manuform/5x6 layout.
QMK Toolbox: A software tool used to flash a new layout onto your keyboard. It is available on Mac and Windows.
Flashing: Refers to when you install software onto your keyboard.
QMK Configurator: A website that allows you to create a custom keyboard layout and export the layout as a
.hexfile. This file is then used in QMK Toolbox.
QMK CLI: QMK's official command line interface tool.
Microcontroller: A microcontroller is a small device that controls your keyboard. Each piece of your keyboard comes with a Pro Micro microcontroller. You may come across it abbreviated as MCU, which stands for MicroController Unit.
Firmware: The software installed on microcontrollers to make your keyboard work. QMK firmware and ZMK firmware are examples.