Here is a glossary of mechanical keyboard terms.
60%: A style of keyboard which is about 60% the size of a full-size keyboard, by means of omitting the top function row, the navigation cluster and the numeric keypad. Access to the missing keys is typically achieved through a Function layer. The Filco Minila is an example of this style.
ABS: a material used for keycaps, provided by default on most Cherry MX keyboards (including Filco and Max Keyboard) and also available as standalone keycap sets. ABS keycaps are generally lighter than their PBT counterparts.
Actuation point: the point at which a key press is recognised by the keyboard. The amount of force required to reach this point is used as a measure of the switch’s stiffness.
Alps: a mechanical switch that was once produced by a Japanese company of the same name. Today, the switch is out of production but has been adapted by companies like Matias into their own switch designs.
ANSI: the standard physical keyboard layout for the United States and the Netherlands, among some other countries. Modern full-size ANSI keyboards generally have 104 keys, including wide Enter and left Shift keys.
Buckling spring: a loud and heavy mechanical switch that uses a large spring that buckles at the actuation point, hence the name. Used by IBM in their Model M, and has since become rather rare. Modern equivalents are produced by Unicomp.
Cherry MX: mechanical switches made by the Cherry Corporation, featuring a distinctive cross shape. Named by their colours (e.g. Cherry MX Red), each of which has a unique combination of weighting and feedback. For more, see our Mechanical Keyboards - Switches above or Intro to Cherry MX mechanical switches. Adapted by Kaihua into Kailh and Razer switches, among others. Cherry MX are the most popular mechanical switches worldwide.
Click: a keyboard or switch that makes an audible “click” sound when pressed. Clicky switches often include a tactile bump as well (see Tactile). Examples of clicky switches include Cherry MX Blue and Matias Click.
Debouncing: as a switch reaches its actuation point, it will bounce around a bit before it comes to rest. Debouncing is the act of correctly interpreting when a key is pressed, without reporting multiple actuations. This is largely a solved problem in modern keyboards.
Full-size: A full-format keyboard, which includes a numeric keypad (for the opposite, see Tenkeyless). Also called by the number of keys included (e.g 105-key for a full-size British keyboard). The Filco Majestouch is an example of this style.
Ghosting: an issue where pressing a combination of three or more keys results in the registering of an addition, unpressed key. Ghosting is prevented by manufacturers by blocking any keys which might be ghosts, but this limits the number of keys that can be pressed simultaneously. See Key Rollover.
ISO: the standard physical keyboard layout for most of the world, with the notable exception of the United States and the Netherlands (see ANSI) and Japan (see JIS). British, German, Spanish, French and Nordic are all examples of ISO layouts, although each has a different logical layout (e.g. the first six letters are QWERTY in the UK and QWERTZ in Germany). Modern full-size ISO keyboards have 105 keys, including tall Enter keys and small left Shift keys.
JIS: the standard physical keyboard layout for Japan (for western layouts, see ANSI and ISO). A modern full-size JIS keyboard has 109 keys, including additional keys to the left and right of the shortened space bar, in order to facilitate entry of characters from various Japanese alphabets.
Key Rollover (#KRO): a limit to how many keys can be simultaneously pressed and correctly registered by the keyboard, often expressed. If you press more keys than your keyboard can register, some key inputs will be missed. Low numbers like 2KRO are typical of low-cost rubber dome keyboards, while 6KRO is the usual standard for a mechanical keyboard. Some keyboards are capable of more; other common figures are 10KRO and NKRO. Modifier keys (e.g. Shift, Ctrl, Alt, Win) do not count towards this limit.
Linear: a keyboard or switch that lacks a tactile bump or click – instead, the resistance increases linearly as the key travels downwards. Examples of linear switches include Cherry MX Red and Cherry MX Black.
Mechanical: a high-quality keyboard or switch that utilises a mechanism with a metal spring in order to register key presses. Many different switch designs fall into this category, including Cherry MX, Alps, Buckling Spring and sometimes Topre.
N-Key Rollover (NKRO): a keyboard with NKRO can register as many keys simultaneously as you care to press down. See Key Rollover.
PBT: a material used for keycaps, provided by default on most Topre and Unicomp keyboards and also available as standalone keycap sets. PBT keycaps tend to wear better and have a slightly more abrasive feel than their ABS counterparts.
Rubber dome: a non-mechanical keyboard that uses a rubber dome to provide resistance and tacticality, mounted above a membrane sheet that registers the key press. Rubber domes are found in the vast majority of keyboards sold, thanks to their low cost.
Tactile: a keyboard or switch that provides feedback you can feel, normally a “bump” or sudden increase in resistance that occurs as the key reaches its actuation point. Examples of tactile switches include Cherry MX Brown and Matias Quiet Click.
Topre: electro-capacitive switches, consisting of a slider in a housing, above a rubber dome, above a coiled spring, above a circuit board. While the switch includes a rubber dome component, it is normally considered a mechanical switch rather than a rubber dome.
Tenkeyless (TKL): A keyboard that does not include a numeric keypad, in order to minimise size and weight. These keyboards can allow for a more comfortable hand position and are more portable, a reasonable tradeoff if you do not often use the numeric keypad. The Filco Majestouch TKL is an example of this style. For the opposite of Tenkeyless, see Full-size.
Travel: the distance that a switch moves from the top to the bottom of a key press. On an average laptop keyboard, key travel is noticeably lower than on the average desktop keyboard.
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