Keymap glossary

Key terms that show up in custom split-keyboard keymaps. Each term has an anchor so other pages can link straight in.

Layer: An overlay that switches the key arrangement. Symbol / number / function layers are typically activated only while a designated key is held.
mo (Momentary Layer): Activate a layer only while the key is held (ZMK &mo N, QMK MO(N)). Releases back to the previous layer. Commonly assigned to a thumb key.
mt (Mod-Tap): A single key that sends a character on tap and a modifier on hold (ZMK &mt MOD KEY). Lets you reach modifiers without leaving the home row.
lt (Layer-Tap): Character on tap, layer hold on hold (ZMK &lt N KEY). Hold Space for a symbol layer is the canonical example.
kp (Key Press): A plain keypress. ZMK &kp A or QMK KC_A — the most basic binding.
trans / none: trans falls through to the binding from a lower layer; none does nothing. Both help avoid accidental keypresses in higher layers.
Combo: Pressing multiple keys (nearly) simultaneously to fire a different key — e.g. F + D = Escape. Adds functionality without adding keys.
Home-row mods: Assign Shift / Ctrl / Alt / GUI to home-row keys via mt. Powerful but tap-term tuning is essential to avoid misfires.
Romaji (Hepburn / Kunrei): Typing Japanese with ASCII letters. Hepburn uses chi / shi / tsu, Kunrei uses ti / si / tu. daken accepts both as correct.
Physical layout: Coordinates describing where each key sits on the board. The i-th binding in a layer maps to the i-th key position.
to (To Layer): Switch to a layer permanently (ZMK &to N, QMK TO(N)). Unlike mo, the layer stays active after release — handy for gaming or numpad modes. Remember to map a way back on the target layer.
sk (Sticky Key / one-shot mod): Applies a modifier to the next single keypress only (ZMK &sk, QMK OSM). Type "sk Shift, then the letter" instead of chording — fewer simultaneous presses, less pinky strain.
Tapping term: The time threshold that separates a tap from a hold on mt / lt keys (ZMK tapping-term-ms, QMK TAPPING_TERM). Too short causes accidental holds during fast typing; too long makes layers feel sluggish. The key tuning knob for home-row mods.
Split keyboard: A keyboard divided into two halves, letting you type with open shoulders. Corne and Lily58 are classic DIY examples. Most have around 40 keys, which makes layer- and combo-heavy keymap design the norm.
Column stagger: Columns are shifted vertically to match finger lengths, unlike the horizontal row stagger of conventional boards. Reaching other rows becomes a straight finger extension — but it takes deliberate practice when migrating.
Thumb cluster: A group of keys placed for the thumbs. Split keyboards typically move Enter / Backspace / layer keys (mo, lt) onto the thumbs, offloading the pinkies onto your strongest digit.
WPM (Words Per Minute): Typing speed where 5 keystrokes count as one word. Around 40 WPM is a common touch-typist baseline. daken shows WPM in drill results so you can track recovery after switching keymaps.
DTS (Devicetree Source): The syntax ZMK keymaps are written in, borrowed from embedded Linux hardware description. It is what's inside a .keymap file. daken parses DTS directly, so you don't need to understand it to load your keymap.