Glossary of competitive gaming gear terms

Sensitivity and aim

Sensitivity vocabulary.
Term	Definition
Yaw	Degrees of horizontal rotation per mouse count at sensitivity 1.0. An engine constant. See constants.
DPI / CPI	Counts the mouse reports per inch of travel. The two terms mean the same thing; CPI is technically more correct. See DPI explained.
eDPI	DPI multiplied by in-game sensitivity. Comparable within one game, meaningless across games. See eDPI.
cm/360	Physical mouse travel for a complete 360 degree turn. The only universal sensitivity unit. See cm/360.
Mouse acceleration	Any system where turn angle depends on movement speed as well as distance. Not the same as a high sensitivity. See acceleration.
Mouse smoothing	Averaging input over several samples. Does not change total rotation, but delays and rounds off changes of direction.
Angle snapping	Firmware straightening near-horizontal movements. Should always be off: it decides you meant a straight line when you did not.
Raw input	Reading the mouse's report stream directly, bypassing the operating system's pointer pipeline and its acceleration.
Monitor distance coefficient	The point on screen at which two fields of view are matched when converting a scoped sensitivity. 0% preserves rotation, 100% preserves screen travel. See MDC.
ADS multiplier	The factor applied to your sensitivity while aiming down sights. See the ADS calculator.

Mice

Mouse vocabulary.
Term	Definition
Polling rate	How many times per second the mouse reports to the PC. Mean added delay is half a report interval. See polling rate.
Lift-off distance (LOD)	The height above the pad at which the sensor stops tracking. Matters most to players who reposition frequently. See sensors.
IPS (sensor)	Inches per second: the fastest surface movement a sensor can track. Modern sensors have four times the headroom a hand can produce.
Debounce delay	The window firmware waits after a contact change, to be sure the switch has stopped bouncing. Pure latency. See switches.
Optical switch	A switch that detects a light beam being interrupted, rather than metal contacts touching. No bounce, therefore no debounce delay.
Hump position	Where the highest point of the shell sits: rear, centre or absent. More informative than the height figure alone. See archetypes.
Palm / claw / fingertip grip	Grip styles defined by which parts of the hand contact the shell. See grip styles.
Skates / feet	The PTFE pads the mouse glides on. A wear item. See skates and glide.
Static / dynamic friction	The force to start a stationary mouse moving, versus the force resisting one already moving. Pads differ in both. See mousepads.

Keyboards

Keyboard vocabulary.
Term	Definition
Actuation point	Depth at which a key press registers, typically 1.0 to 2.2 mm. See actuation point.
Reset point	Depth to which the key must return before it can fire again.
Hysteresis	The gap between actuation and reset. Large hysteresis makes fast re-presses require more movement.
Total travel	Depth at which the key bottoms out, typically 3.4 to 4.0 mm.
Hall effect switch	A switch sensing a magnet's position rather than a contact closing, so it reports depth continuously. See Hall effect.
Rapid trigger	Releasing a key as soon as it begins moving up, by a configurable distance, rather than at a fixed reset depth.
SOCD	Simultaneous opposing cardinal directions: what happens when you hold both A and D. Automatic resolution of this is restricted in several titles.
NKRO	N-key rollover: reporting any number of simultaneous key presses correctly. See NKRO.
Ghosting	A keyboard reporting a key you did not press, caused by missing isolation diodes. Does not occur on mechanical keyboards.
TKL, 65%, 60%	Layout sizes, defined by which key clusters are removed. See layouts.

Display and latency

Display and latency vocabulary.
Term	Definition
Frame time	How long an individual frame took, in milliseconds. 1000 divided by framerate. The honest unit. See frame time.
1% low	The framerate corresponding to the slowest 1% of frames. Tracks perceived smoothness far better than the average.
Render queue	Frames the CPU has prepared ahead of the GPU. The largest variable latency term in most setups. See Reflex.
Click to photon	Total latency from input to the first photon showing its result. See the chain.
Scan-out wait	The time a finished frame waits for the display to begin drawing. Mean is half a refresh interval without VRR.
GtG response time	Grey-to-grey: how long a pixel takes to change shade. Varies enormously by which shades. See response time.
Overdrive	Driving a pixel past its target voltage to change it faster. Too much produces overshoot, seen as a bright trail.
Persistence blur	Smearing caused by a frame being held still while your eyes track a moving object. Proportional to display time per unique frame. See motion clarity.
Backlight strobing / BFI	Flashing the backlight briefly per frame instead of holding it, cutting persistence blur at the cost of brightness and flicker.
VRR	Variable refresh rate: the display refreshes when a frame is ready rather than on a fixed schedule. See VRR.
Pixels per degree	Pixels falling into one degree of your visual field. Combines resolution, size and distance. Roughly 60 is the acuity limit. See the calculator.
Tick rate	How many times per second a game server advances the world and sends updates. See network latency.
Peeker's advantage	The attacker seeing the defender first when rounding a corner, caused by the time information takes to travel. Not a bug.
Lag compensation	The server rewinding the world to when you fired, to validate your shot against what you saw.

Audio and controllers

Audio and controller vocabulary.
Term	Definition
HRTF	Head-related transfer function: the filtering your head and outer ear apply to sound by direction. Engine-level HRTF is useful; post-mix virtual surround usually is not. See positional audio.
Interaural time / level difference	The two strong localisation cues: arrival time and loudness difference between your ears. Headphones reproduce both accurately.
Cone of confusion	The set of positions your ears cannot distinguish from timing and level cues alone, which is why front and back get confused.
Auditory masking	A loud sound raising your hearing threshold at nearby frequencies. Why bass boost hides footsteps. See EQ.
Deadzone	A region near a stick's centre where input is ignored, to prevent drift. See deadzones.
Response curve	How stick deflection maps to turn speed. Linear, exponential or dual-zone. See response curves.
Rotational aim assist	Added rotation that helps your view follow a moving target, active only while you provide stick input. See aim assist.
Stick drift	Unintended input from a worn potentiometer stick. Magnetic sticks remove the wear mechanism. See Hall effect sticks.

Frequently asked questions

What is the difference between eDPI and cm/360?

eDPI is DPI multiplied by in-game sensitivity, and it is only comparable within one game because each engine applies a different rotation constant. cm/360 is the physical distance your mouse travels for a full turn, and it means the same thing in every game, on every mouse, at every DPI.

What does yaw mean in a game sensitivity context?

The number of degrees your view rotates for each mouse count received, at sensitivity 1.0. It is an engine constant: 0.022 in Source games, 0.07 in Valorant, 0.0066 in Overwatch 2 and modern Call of Duty.

What is rapid trigger?

A Hall effect keyboard feature where a key releases as soon as you begin lifting it, by a configurable distance, rather than waiting for it to rise past a fixed reset point. It makes release timing constant regardless of how deeply you pressed.

What is click-to-photon latency?

The total time from a physical input to the first photon leaving your monitor carrying its visual consequence. It is the sum of switch debounce, report wait, radio hop, input sampling, simulation, render queue, GPU render, scan-out wait and panel response.