Glossary of Computer Terms

Introduction

Computer science has its own vocabulary — hundreds of technical terms that you need to understand clearly. When studying for exams or preparing for interviews, having precise definitions at your fingertips makes a significant difference. This glossary covers the most important terms you will encounter in your Computer Fundamentals course, written in clear language with brief explanations that help you understand each concept rather than just memorize its definition.

Use this page as a quick-reference companion to your studies. When you encounter an unfamiliar term in another chapter, look it up here for a concise explanation. Terms are grouped by topic area for easier browsing during study sessions.

Hardware Terms

ALU (Arithmetic Logic Unit): The component of the CPU that performs all arithmetic operations (addition, subtraction, multiplication, division) and logical operations (comparisons, AND, OR, NOT).

BIOS (Basic Input/Output System): Firmware stored on a chip on the motherboard that initializes hardware during boot-up and provides basic I/O services before the operating system loads. Largely replaced by UEFI in modern systems.

Bus: A communication pathway that transfers data between computer components. Types include data bus (carries data), address bus (carries memory addresses), and control bus (carries control signals).

Cache Memory: Small, very fast memory located between the CPU and RAM that stores frequently accessed data for quick retrieval, reducing the time the CPU spends waiting for data from slower RAM.

CPU (Central Processing Unit): The primary component of a computer that executes program instructions. Contains the ALU, Control Unit, and registers.

GPU (Graphics Processing Unit): A specialized processor designed for rendering graphics and performing parallel computations. Essential for gaming, video editing, and machine learning.

Motherboard: The main printed circuit board in a computer that connects and allows communication between all hardware components including CPU, RAM, storage, and peripherals.

Peripheral: Any device connected to a computer externally — keyboards, mice, printers, scanners, webcams, and external storage devices.

RAM (Random Access Memory): Volatile memory that temporarily stores data and programs currently being used by the CPU. Data is lost when power is turned off.

ROM (Read Only Memory): Non-volatile memory that permanently stores essential instructions (like BIOS) that do not change during normal operation.

SSD (Solid State Drive): A storage device that uses flash memory chips with no moving parts, providing faster access speeds, lower power consumption, and better durability than traditional hard drives.

UEFI (Unified Extensible Firmware Interface): Modern replacement for BIOS that provides a graphical interface, faster boot times, secure boot, and support for larger hard drives.

Software Terms

Algorithm: A step-by-step, finite procedure for solving a specific problem or performing a specific task, independent of any programming language.

API (Application Programming Interface): A set of rules and protocols that allow different software applications to communicate with each other.

Compiler: A program that translates an entire high-level language source code file into machine code (an executable) before the program runs.

Driver (Device Driver): Software that allows the operating system to communicate with specific hardware devices. Each device type requires its own driver.

Firmware: Software permanently embedded in hardware (stored in ROM or flash memory) that provides low-level control of the device.

IDE (Integrated Development Environment): A software application providing comprehensive facilities for programming — code editor, compiler/interpreter, debugger, and build tools in one package.

Interpreter: A program that translates and executes high-level source code line by line during runtime, without creating a separate executable file.

Kernel: The core component of an operating system that manages system resources, handles hardware communication, and provides essential services to other software.

Open Source: Software whose source code is freely available for anyone to view, modify, and distribute under specific licenses.

Operating System (OS): System software that manages hardware resources, provides user interfaces, and runs applications. Examples: Windows, Linux, macOS, Android, iOS.

Networking Terms

Bandwidth: The maximum rate of data transfer across a network connection, measured in bits per second (bps, Mbps, Gbps).

DNS (Domain Name System): The system that translates human-readable domain names (like google.com) into IP addresses (like 142.250.180.14) that computers use to identify each other.

Firewall: A network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules.

HTTP/HTTPS: Hypertext Transfer Protocol — the foundation of web communication. HTTPS adds encryption (TLS) for secure data transfer.

IP Address: A unique numerical identifier assigned to each device on a network. IPv4 uses 32 bits; IPv6 uses 128 bits.

ISP (Internet Service Provider): A company that provides internet access to customers through various technologies (fiber, cable, DSL, wireless).

LAN (Local Area Network): A network covering a small area (building or campus) with high speed and low cost.

Protocol: A set of rules governing how data is formatted, transmitted, and received over a network. Enables different devices to communicate.

Router: A networking device that forwards data packets between different networks, making routing decisions based on IP addresses.

TCP/IP: The fundamental protocol suite of the internet — TCP ensures reliable delivery while IP handles addressing and routing.

VPN (Virtual Private Network): Technology that creates a secure, encrypted connection over a public network, allowing remote access to private network resources.

Security Terms

Authentication: The process of verifying the identity of a user, device, or system — confirming "you are who you claim to be."

Encryption: Converting data into an unreadable format (ciphertext) that can only be decoded with a specific key, protecting data from unauthorized access.

Malware: Any software intentionally designed to cause damage — includes viruses, worms, trojans, ransomware, and spyware.

Phishing: A social engineering attack that uses fake emails, messages, or websites to trick victims into revealing sensitive information.

Two-Factor Authentication (2FA): Security method requiring two different types of identification — typically something you know (password) plus something you have (phone for OTP).

Data Terms

Binary: A number system using only two digits (0 and 1) that forms the foundation of all computer data representation.

Bit: The smallest unit of data in computing — a single binary digit (0 or 1).

Byte: A unit of data consisting of 8 bits, capable of representing 256 different values (0-255). The standard unit for measuring file sizes.

Database: An organized collection of structured data stored electronically, managed by a Database Management System (DBMS).

Key Takeaways

• Technical vocabulary is essential for clear communication in computing
• Understanding definitions helps you construct better exam answers
• Many terms have relationships — understanding one helps you understand related concepts
• This glossary covers the most commonly tested terms in BCA Computer Fundamentals courses
• Return to this page whenever you encounter an unfamiliar term in your studies
• Being able to define terms precisely demonstrates foundational knowledge in interviews