abstraction (process) – managing complexity through selecting and capturing relevant information about a thing, a system or a problem, or hiding at a lower level operational details.

abstraction (product) – a representation of a thing, a system or a problem that contains only selected (relevant) details about its state and/or behaviour; for example, a diagram is an abstraction.

Acceptable Use Policy (AUP) - An Acceptable Use Policy comprises a set of rules applied by the owner/manager of a network, website or large computer system that defines the ways in which the network, site or system may be used.

algorithm – a set of unambiguous rules or a sequence of instructions to achieve a particular objective.

array – a data structure comprising a collection of values of the same type, accessible through an index; arrays include lists but can have more than one dimension.

assembly code – a human-readable programming language in which each instruction corresponds to a single executable instruction for a CPU.

binary – the base 2 number system, and a method of encoding data using two symbols, 1 and 0.

binary number – a number written in the base 2 number system.

bit – a basic unit of data that stores one binary value, 1 or 0.

bitmap – a collection of pixels forming an image.

Boolean – a system of logic, in which statements are represented as allowed combinations of predicates which are either TRUE or FALSE, with formal rules for working with such statements; a data type with only two values, TRUE or FALSE.

browser cookie – a small piece of text recording activity about websites you visit, stored on your computer.

circuit – a grouping of electronic components that allow for operations to be performed.

code – any sequence of instructions or set of rules expressed in a programming language.

coding – taking the ideas of an algorithm and expressing them in the formal code of a programming language.

colour depth – the number of different colours that may be used in an image, dictated by the number of bits used to represent the colour of each pixel.

command – An instruction for the computer to execute, written in a particular programming language.

compiler – a program that converts programs written in one language (source code) into equivalent programs written in a different language (often in the form of instructions that a processor can execute, i.e. machine code).

computational thinking – looking at problems and systems in such a way that a computer can help us solve or understand them.

CPU – central processing unit; the device within a computer that executes instructions.

Creative Commons – A licensing scheme where the creator of an original work allows others to use it without seeking further permission, subject to a number of agreed conditions – www. creativecommons.org.

data – A structured set of numbers, possibly representing digitised text, images, sound or video, which can be processed or transmitted by a computer, also used for numerical (quantitative) information.

data structure – a particular way to store and organise data within a computer program.

decimal / denary – the base 10 number system.

decomposition – breaking a problem or system down into its components.

digital – representing information using discrete numerical values.

digital artefact – digital content made by a human with intent and skill.

digital creator – a person who makes digital artefacts.

digital media – media encoded in a computer readable form.

Domain Name Service (DNS) – The distributed automatic system that converts domain names into the IP addresses which are used for routing packets via the internet.

encrypt – To securely encode information so that it can only be read by those knowing both the system used and a secret, private key.

function - a program module which, like a function in mathematics, transforms an input value into an output value according to a set of rules or a sequence of steps.

generalisation – A computational thinking process in which general solutions or models are preferred to or derived from particular cases.

hardware – the physical components that make up a computer.

HTML – hypertext mark-up language; the language used to create web pages.

Hypertext Transfer Protocol (HTTP) – HTTP is the standard protocol for the request and transmission of HTML web pages between browser and web server.

identity - who a person is; that which distinguishes them from another but remains (broadly) stable over time.

input – data provided to a computer system, such as via a keyboard, mouse, microphone, camera or physical sensors.

interface – The boundary between one system and another.

internet – a global network of interconnected networks.

interpreter – a program that converts instructions written in one language into equivalent instructions in another language, typically executing each instruction as soon as it is translated.

IP address – Internet Protocol address; a unique numeric value that is assigned to a computer or other device connected to the internet so that it may be identified and located.

lists – a data structure for storing ordered (although not necessarily sorted) values.

loop – A block of code repeated automatically under the program’s control.

logical reasoning - to make deductions or inference according to a set of accepted rules from given premises.

model – a representation of (some part of) a problem or a system.

modelling – the act of creating a model.

modular design – the practice of designing a system or program as a set of independent but interacting units (modules) that may be implemented and tested separately before bringing them together to solve the overall problem.

network – the computers and the connecting hardware (wifi access points, cables, fibres, switches and routers) that make it possible to transfer data using an agreed method (‘protocol’).

online safety – used to describe behaviours and policies intended to minimise the risks to a user of using digital technology, particularly the internet.

open source software – Software in which the source code is made available for others to study, and typically adapt, usually with few if any restrictions.

operating system – The programs on a computer which deal with internal management of memory, input/output, security and so on, such as Windows 10 or iOS.

output – The information produced by a computer system for its user, typically on a screen, through speakers or on a printer, but possibly through the control of motors in physical systems.

packet – more precisely, a network packet. A formatted unit of data for transmission across a network. Each packet contains part of a message plus some additional data, including where it is from and where it is going.

Packets of data – A small set of numbers that get transmitted together via the internet, typically enough for 1000 or 1500 characters.

pixel – the smallest controllable element of a picture/display.

privacy - ensuring that information is only available to those to whom its owner has chosen.

procedure - a program module which may take any number of arguments and may return a result; it may change the state of other parts of the computer system on which it is executed.

process – the act of using data to perform a calculation or other operation.

program – a sequence of instructions or set of rules, expressed as code that the computer executes in order to achieve a particular objective.

programming – the craft of analysing problems and designing, writing, testing and maintaining programs to solve them.

programming language – formal language used to give a computer instructions, for example Scratch or Python.

repetition – the process of repeating a task a set number of times or until a condition is met.

resolution – a measurement of the number of pixels needed to display an image.

router – more precisely, a network router. A router is a device that connects networks to one another, and directs packets between networks. A home broadband router performs the functions of a switch while allowing computers to connect to the internet.

screencast – a recording of on-screen action that is often accompanied by an audio narration.

security - ensuring that data or systems are not available to those unauthorised to access it and that it is available to those who are so authorised.

script – a computer program typically executed one line at a time through an interpreter, such as the instructions for a Scratch character.

selection – a programming construct in which one section of code or another is executed depending on whether a particular condition is met.

sequence – an ordered set of instructions.

server – a computer dedicated to a particular set of tasks that provides services to other computers on a network.

simulation – Using a computer to model the state and behaviour of real-world (or imaginary) systems, including physical or social systems; an integral part of most computer games.

software – the programs that run on the hardware/computer system.

search - to identify data which meets particular criteria

sort - to take a data structure such as a list and return it with the values in order.

sprite – A computer graphics object that can be controlled (programmed) independently of other objects or the background.

switch – more precisely, a network switch. This is a device that connects multiple computers to one another on a single local area network (LAN), and directs packets from machine to machine.

table – a data structure storing organised sets of data under column headings.

Unicode – a standardised system for representing individual characters as sequences of bits.

Uniform Resource Locator (URL) – A standard for specifying the location on the internet of certain files.

variable – a simple data structure, in which (typically) a single value is referenced by a name.

web browser – a computer program to view websites.

web server – A service running on a computer (or sometimes for the computer itself) that returns HTML data for a web page when it receives an HTTP request via the local network or the internet.

World Wide Web – A service provided by computers connected to the internet (web servers), in which pages of hypertext (web pages) are transmitted to users.

The above was originally written as an appendix for the KS3 QuickStart Handbook, but wasn’t included in the final version as published. It draws on my Primary QuickStart Handbook glossary and Pete Kemp’s Computing in the National Curriculum: a Guide for Secondary Teachers. A definitive and comprehensive glossary for computing is published by the BCS.