start glossary

docs/_summary.md

@@ -16,6 +16,7 @@
   * [Mouse keys](mouse_keys.md)
 
 * Reference
+  * [Glossary](glossary.md)
   * [Keymap overview](keymap.md)
   * [Keycodes](keycodes.md)
     * [Basic Keycodes](basic_keycodes.md)

docs/glossary.md

@@ -0,0 +1,10 @@
+# Glossary of QMK terms
+
+git
+: versioning software used at the commandline
+
+keymap
+: an array of keycodes mapped to a physical keyboard layout, which are processed on key presses and releases
+
+matrix
+: a wiring pattern of columns and rows (and usually diodes) that enables the MCU to detect keypresses with a fewer number of pins