Technology

Kevin Systrom American entrepreneur and programmer best known as co‑founder and former CEO of Instagram; known for product design, photography focus, and the app's role in online visual culture.

Key (device for operating locks and access control) Key A key is a tool—mechanical or electronic—used to operate locks and control access; it includes many designs from simple cut metal blades to modern smart and transponder keys.

Key derivation function (KDF) Key derivation function A key derivation function (KDF) produces cryptographic keys from a secret input (such as a password or shared secret). It adds structure, salts, and computational cost to improve s…

Key Distribution Center (KDC) in Cryptography Key distribution center A key distribution center (KDC) is a trusted service that issues and manages cryptographic keys and tickets to enable secure authentication and controlled access within a networked…

Key generation: principles, methods, and practical considerations Key generation Overview of cryptographic key generation: how keys are created, sources of randomness, symmetric vs. public-key methods, recommended sizes, management practices, attacks and mitiga…

Key space (cryptography) Key space A key space is the complete set of possible keys usable by a cryptographic algorithm. Size, distribution and weak keys determine resistance to guessing and brute-force attacks.

Key-agreement protocol (cryptographic key exchange) Key-agreement protocol A key-agreement protocol lets two or more parties jointly derive a shared secret key so that each participant influences the outcome and outsider knowledge is minimized.

Keyboard (computer and musical interface) Keyboard An overview of keyboards as input devices and musical interfaces: forms, components, historical development, common layouts and uses, and distinctions between electronic and acoust…

Computer keyboard: design, history, functions and variations Keyboard (computer) Comprehensive overview of the computer keyboard: how it works, key layouts and switches, connectivity, history, common uses, accessibility features and notable variations.

Keychain: Uses, Types, Design, and History Keychain Concise guide to keychains: what they are, how they are made, major parts and types, historical development, common uses and examples, and practical notes on selection and safety.

Keynote (software) Keynote is Apple's presentation application for macOS and iOS, part of the iWork suite. It focuses on visual design, templates, animations and cloud syncing, with import/export com…

Keystroke logging (keylogging): methods, history, uses and countermeasures Keystroke logging Keystroke logging records keys typed on a device. This article explains how keyloggers work, common types, historical development, legitimate and illicit uses, and detection and pr…

Kibibyte (KiB): Binary unit of digital information equal to 1,024 bytes Kibibyte Definition, usage, and conversions for the kibibyte (KiB): the binary unit equal to 1,024 bytes, its role among binary prefixes, and how it differs from decimal kilo-based measures…

Kill switch (emergency stop) Kill switch A kill switch, or emergency stop, is a control that halts machinery or processes rapidly to prevent harm. This article covers functions, types, design principles, standards, applic…

Kilobit — unit of digital information (1,000 bits) Kilobit A kilobit (kbit) is an SI-based unit equal to 1,000 bits. It is commonly used for data rates and is distinct from the 1,024‑bit binary unit, the kibibit.

Kilobyte: definition, history, and usage in computing Kilobyte Kilobyte (kB) is a unit for digital information roughly equal to one thousand bytes; historically used for 1024 bytes as well. This article explains definitions, causes of ambiguit…

Kinect: Microsoft’s Motion-Sensing Camera and Voice Interface Kinect Kinect is a motion-sensing input device by Microsoft for consoles and other systems, combining depth-sensing cameras and microphones to enable gesture, voice and body-tracking inte…

Kirby & the Amazing Mirror A 2004 Game Boy Advance Kirby title notable for its non‑linear exploration, multiplayer linkage, and the unusual absence of King Dedede in the cast.

Kirby's Tilt 'n' Tumble A Game Boy Color spin-off starring Kirby that used a built-in accelerometer to let players tilt and jerk the handheld to move the character and solve time-limited puzzle stages.

Kitchen stove — types, history, and common uses Kitchen stove An overview of kitchen stoves: how they work, main types (solid fuel, gas, electric, induction), historical development, common components, uses, safety and environmental considera…

Knife: form, function, history, and common types Knife A knife is a hand tool or weapon with a sharpened edge used for cutting and shaping. This article outlines its parts, materials, historical development, common types, uses, and saf…

Knob — types, design, history, and uses Knob A knob is a small rounded handle or protrusion used for turning, pulling or adjusting. This article covers common types, materials, ergonomics, installation, control knobs and acce…

Knoppix: a Live Debian-based Linux distribution Knoppix Knoppix is a Debian-based live Linux distribution created by Klaus Knopper. It boots from removable media, auto-detects hardware, and runs programs from compressed images with on-t…

KOffice: KDE's integrated office suite (historical overview) KOffice KOffice was a free, open-source office suite developed for the KDE desktop. It included word processing, spreadsheet, presentation and graphics tools, used OpenDocument formats and…

KPresenter (KDE presentation program) KPresenter KPresenter is a free, open-source presentation application from the KOffice suite for the KDE desktop. It uses an XML+ZIP native format and can import several common presentation t…

Kubuntu — Ubuntu with the KDE Plasma desktop Kubuntu Kubuntu is an official Ubuntu flavor that replaces Ubuntu's default GNOME desktop with the KDE Plasma environment and related applications, aimed at users who prefer KDE tooling an…

KWord — a frame-based word processor from the KOffice/KDE ecosystem KWord KWord is a free, frame-oriented word processor originally developed for the KOffice suite and the KDE desktop. It emphasizes layout flexibility, graphic embedding and linked text f…

Ladder: Types, Construction, Uses, History and Safety Ladder Overview of ladders: structure and materials, common types (step, extension, fixed, rope), historical notes, principal uses and practical safety guidance for domestic and professio…

Lag (delay and latency in computing and gaming) Lag Lag is the perceived or measured delay between an action and its effect in computing, networks, gaming, and multimedia. Causes, measurements, examples, and common mitigation strate…

Lamborghini Diablo — V12 Grand Touring and Supercar (1990–2001) Lamborghini Diablo The Lamborghini Diablo is a mid-engined V12 sports car produced 1990–2001 in Sant'Agata Bolognese. It succeeded the Countach, spawned multiple variants, and was followed by the Mur…

Lamp: device for artificial lighting — types, parts, history and uses Lamp An overview of lamps: what they are, main components and types, historical development from candles to electric lamps, practical uses, and notable distinctions such as efficiency a…

Lancia Dedra Compact executive car produced by Lancia from 1989 until the late 1990s; built on Fiat's Type Three platform and available as saloon and estate with petrol Twin Spark and diesel op…

Lantern A lantern is a portable device that produces light for travel, signaling, work, decoration, and religious or seasonal festivals.

Laptop: portable personal computer and its design, uses, and evolution Laptop A laptop is a compact, portable personal computer that combines display, keyboard and input devices in a single folding chassis; used for work, study, gaming, and mobile computing.

Laser printer: technology, components, history and uses Laser printer A laser printer uses focused light and toner to create images on paper. This article explains how laser printers work, their main parts, history, advantages and drawbacks, and comm…

LaserDisc: early consumer optical-video format Laserdisc LaserDisc is an early optical disc format for analog video and digital audio, introduced in 1978. It offered better picture than VHS, was larger than later DVDs, and remained a col…

Latch (mechanical fastener) Latch A latch is a simple mechanical fastening device used to hold two components together. It permits quick opening and closing while resisting accidental or unwanted movement.

Launch pad: design, components, history and operational roles Launch pad Comprehensive overview of launch pads: purpose, main parts, materials, historical development, operational use for rockets and spacecraft, and safety and environmental consideratio…

Lawn mower — types, function, history, and safe use Lawn mower Comprehensive overview of lawn mowers: how they work, common types (push, rotary, ride-on, robotic), maintenance and safety, plus a brief history from early reel designs to modern…

Leaf blower: overview, types, uses, history and environmental considerations Leaf blower A power tool that moves yard debris with directed air. Covers types (handheld, backpack, walk-behind), power sources, blower-vacuum variants, uses, history, and environmental and s…

LEGO: history, design, uses, and cultural impact Lego LEGO is a system of interlocking plastic construction pieces and themed sets created by the Danish LEGO Group; it spans play, education, engineering and a global fan culture.

Lego Duplo: an introduction to the larger-scale Lego system for young children Lego Duplo Lego Duplo is LEGO’s larger-scale building system introduced in 1969 for toddlers and preschoolers. It features oversized bricks, simple figures and age-appropriate sets that can c…

Letter bomb An explosive device hidden inside mailed correspondence or a small package, intended to detonate when handled or opened; used historically for assassination, intimidation, and sabo…

Lever-action firearms: design, history, and uses Lever-action firearms An accessible overview of lever-action firearms covering their mechanism, development from the 19th century, notable models, practical uses, and strengths and limits.

LG Prada (KE850) — early fashion-branded touchscreen mobile phone LG Prada The LG KE850, sold as the Prada Phone, is a 2007 collaboration between LG Electronics and Prada that paired a minimalist touchscreen interface with fashion-oriented design and help…

Light bulb: design, history, types, and uses Light bulb Overview of the light bulb — how it works, main types (incandescent, fluorescent, LED, gas-discharge), historical development, common uses and environmental considerations.

Light-emitting diode (LED): principles, design, history and uses Light-emitting diode A light-emitting diode (LED) is a semiconductor device that emits light when electrically biased. This article explains how LEDs work, their structure, development, common uses and…

Lighter: portable flame-producing device Lighter A lighter is a small portable device that creates a flame or heat source on demand. It includes designs from early chemical lamps to modern butane, piezoelectric and electric car l…