Nepal SEE Computer Science key terms

An electronic device that accepts data, processes it according to stored instructions, and produces useful output. It combines hardware and software to perform fast, accurate and automatic work.

Raw, unprocessed facts, figures, symbols or observations that have no meaning on their own. Data becomes information only after it is organised, processed or interpreted by a person or a computer.

Meaningful and processed data that helps people make decisions. It is the result of applying operations such as sorting, calculating, summarising or comparing to raw data.

The physical, tangible parts of a computer that can be seen and touched, such as the keyboard, monitor, motherboard, hard disk and printer. Hardware alone cannot work without instructions.

A set of programs, instructions and related data that tells the hardware what to do. It is intangible and is divided mainly into system software and application software.

Any hardware used to enter data and instructions into a computer, for example a keyboard, mouse, scanner, microphone or touchscreen. It converts human actions into signals the computer can process.

Hardware that presents processed results to the user in a form they can understand, such as a monitor, printer, speaker or projector. Soft copy is displayed; hard copy is printed on paper.

The central processing unit, often called the brain of the computer. It fetches, decodes and executes instructions and contains the control unit, arithmetic logic unit and registers.

The arithmetic logic unit inside the CPU that performs all arithmetic operations such as addition and subtraction and all logical comparisons such as greater than, less than and equal to.

The part of the CPU that directs and coordinates other components. It fetches instructions, decodes them and sends control signals so that each operation happens in the correct sequence.

Memory the CPU can access directly, such as RAM and ROM. It is fast but limited in size, and RAM loses its contents when power is switched off.

Random Access Memory, a volatile read-write memory that temporarily holds the programs and data currently in use. Its contents are erased when the computer is switched off.

Read Only Memory, a non-volatile memory whose contents are written during manufacture and normally cannot be changed by the user. It stores the start-up instructions needed to boot the computer.

Non-volatile storage used to keep data and programs permanently, such as hard disks, SSDs, pen drives and DVDs. It is slower than primary memory but has much larger capacity and lower cost per byte.

System software that manages hardware, memory, files and processes and provides a platform for application programs. Examples include Windows, Linux, macOS and Android.

Software designed to help users perform specific tasks, such as word processors, spreadsheets, presentation tools, browsers and games. It depends on the operating system to run.

Small programs that help maintain, protect or optimise a computer system, for example antivirus tools, disk cleanup, backup programs and file compression tools. They support the operating system rather than doing user work.

A systematic way of representing numbers using a fixed set of digits and a base. Common systems are binary (base 2), octal (base 8), decimal (base 10) and hexadecimal (base 16).

A base-2 number system that uses only the digits 0 and 1. Each position represents a power of two, and computers use it because electronic circuits have two stable states, off and on.

The base-10 number system that uses the digits 0 to 9 and is used in everyday life. Each position represents a power of ten, such as units, tens and hundreds.

A base-16 number system that uses digits 0 to 9 and letters A to F. It is used as a short, readable way to write long binary values such as memory addresses and colour codes.

The smallest unit of digital data, represented by a single binary digit, either 0 or 1. Combinations of bits encode all numbers, text, images and instructions in a computer.

A group of eight bits treated as one unit. One byte can store 256 different values and typically represents one character of text in ASCII encoding.

American Standard Code for Information Interchange, a character encoding that assigns a 7-bit numeric code to letters, digits, punctuation and control characters. It allows text to be stored and exchanged consistently.

A universal character encoding standard that gives a unique code point to characters of most of the world's writing systems, including Devanagari. It overcomes the limited character set of ASCII.

A finite, step-by-step set of clear instructions for solving a problem or completing a task. It must produce a result in a limited number of steps and work for all valid inputs.

A diagram that shows the steps of an algorithm using standard symbols such as ovals for start and stop, parallelograms for input and output, rectangles for processes and diamonds for decisions, joined by arrows.

A structured, English-like description of an algorithm that follows programming logic without the strict syntax of a real language. It helps plan a program before it is coded.

A named storage location in memory whose value can change while a program runs. Each variable has a name, a data type and a current value.

A named value that is fixed when the program is written and cannot be changed during execution, such as the value of pi. It protects important values from accidental modification.

A classification that defines what kind of values a variable can hold and what operations are allowed on them. Common types are integer, real, character, string and boolean.

A program statement that introduces a variable or constant by giving its name and data type before it is used, for example DIM age AS INTEGER. It lets the compiler reserve memory.

A symbol that performs an operation on one or more values, called operands. Operators are arithmetic, relational, logical or string operators, and they follow a fixed order of precedence.

A control structure that runs a block of code only when a condition is true, or chooses between alternatives. Common forms are IF...THEN, IF...THEN...ELSE and SELECT CASE.

A control structure that repeats a block of statements while a condition holds or for a fixed number of times. Examples are FOR...NEXT, WHILE...WEND and DO...LOOP.

An organised collection of related data stored so that it can be easily accessed, managed and updated. A database management system such as MS Access is the software used to work with it.

Database Management System, software that lets users create, store, query, update and protect databases. It handles security, backup and concurrent access so users need not manage files directly.

A field or set of fields that uniquely identifies each record in a table. It cannot contain duplicate values or nulls and is used to link tables together.

A field in one table that refers to the primary key of another table, creating a relationship between them. It enforces referential integrity by preventing records that point to nothing.

Two or more computers connected by communication media so they can share data, hardware and software. Networks are classified by size as LAN, MAN and WAN.

Local Area Network, a network covering a small area such as a room, building or campus. It is usually privately owned, offers high speed and uses cables or Wi-Fi.

Wide Area Network, a network that spans a large geographical area such as a country or the whole world. It often uses public communication links and is more expensive and slower than a LAN.

A global network of interconnected networks that lets computers exchange information using common protocols such as TCP/IP. It supports services like the web, email and file transfer.

A unique numeric address assigned to each device on a network so data can be sent to the correct destination. IPv4 uses four numbers from 0 to 255 separated by dots.

Uniform Resource Locator, the address used to locate a resource on the web. It includes the protocol, domain name and path, for example https://example.com/page.html.

The integration of different media types such as text, graphics, animation, audio and video into one digital presentation. It makes content more engaging but requires more storage and processing power.

Any illegal activity carried out using computers or the internet, such as hacking, phishing, identity theft, cyberbullying and software piracy. It is punishable under Nepal's Electronic Transactions Act.

A cyber attack in which criminals send fake messages or build imitation websites to trick people into revealing passwords, bank details or personal information. Users should check links and never share credentials.

The set of moral principles that guide the acceptable use of computers and networks. It covers honesty, respect for privacy, avoiding harm, not copying software illegally and respecting others' work.

The illegal copying, distribution or use of software without a valid licence. It harms developers, spreads malware and is punishable by law, so only licensed or free software should be used.