Maharashtra HSC IT Commerce key terms

Raw, unprocessed facts and figures such as numbers, text, or symbols that on their own carry little meaning until they are organised or interpreted. In computing, data is the input that programs collect, store, and transform into useful information.

Data that has been processed, organised, or interpreted so it becomes meaningful and useful for decision-making. For example, a list of marks becomes information once it is totalled and averaged into a result.

The smallest unit of digital data, holding exactly one of two states represented as 0 or 1. Bits are grouped into bytes, and every file, image, and instruction in a computer is ultimately stored as a pattern of bits.

A group of eight bits treated as one unit, commonly used to store a single character such as a letter or digit. Storage sizes such as kilobyte, megabyte, and gigabyte are all multiples of the byte.

A base-2 number system that uses only the digits 0 and 1, matching the two voltage states a digital circuit can reliably represent. Converting decimal numbers to binary is a standard skill for understanding how computers store values.

The main processing chip of a computer that fetches instructions, decodes them, and executes arithmetic and logical operations. It coordinates other components and is often described as the brain of the computer.

Fast, directly accessible memory such as RAM and ROM that the CPU reads and writes while the computer is running. RAM is volatile and loses its contents on power-off, while ROM retains firmware permanently.

Non-volatile storage such as hard disks, SSDs, and pen drives that keeps data permanently even when power is switched off. It is slower than primary memory but far larger and cheaper per unit of capacity.

Hardware used to enter data and commands into a computer, for example a keyboard, mouse, scanner, or microphone. It converts human actions or physical signals into a form the computer can process.

Hardware that presents processed results to the user, such as a monitor, printer, or speaker. It converts the computer's internal digital signals into text, images, sound, or printed pages that people can perceive.

System software that manages hardware resources, runs application programs, and provides a user interface. It handles tasks like memory allocation, file management, and process scheduling so applications do not need to control hardware directly.

A user interface built from visual elements such as windows, icons, menus, and a pointer, allowing users to interact through clicking and dragging. It contrasts with a command-line interface, where users type text commands.

The method an operating system uses to name, organise, store, and retrieve files on a storage device, typically through folders and a directory tree. Examples include FAT32, NTFS, and ext4.

The ability of an operating system to run several processes apparently at the same time by rapidly switching CPU time between them. Each process gets short time slices, giving the impression of simultaneous execution.

Software whose source code is published under a licence that allows anyone to study, modify, and redistribute it. Examples include Linux, LibreOffice, and the Apache web server; the opposite model is proprietary or closed-source software.

A markup instruction written in angle brackets, such as

or , that tells a browser how to treat the content it surrounds. Tags usually come in pairs with an opening and a closing form.

A complete structural unit of an HTML document made of a start tag, its content, and an end tag, for example

Heading. Elements define the meaning and structure of page content such as headings, lists, and paragraphs.

A name-value pair written inside an HTML start tag that supplies extra information, such as src in an image tag or href in a link. Attributes modify how an element behaves or displays.

A stylesheet language used to control the appearance of HTML documents, including colour, fonts, spacing, and layout. Separating style rules from markup keeps pages easier to maintain and reuse.

The part of a CSS rule that identifies which HTML elements the declarations apply to, for example a tag name, a class written with a dot, or an id written with a hash. Selectors let one rule style many elements at once.

A scripting language that runs in the browser to make web pages interactive, handling events, validating forms, and updating content without reloading the page. It is also used on servers through environments such as Node.js.

A tree-shaped representation of an HTML page that scripts can read and modify. Each element becomes a node, so JavaScript can change text, styles, or structure dynamically through DOM methods.

A function that runs in response to a user or browser action, such as a click, keypress, or page load. It is attached to an element either as an HTML attribute or through JavaScript listeners.

A named storage location in a program that holds a value which can be read or changed while the program runs. In JavaScript, variables are declared with let, const, or the older var keyword.

A reusable block of code that performs a specific task and can accept inputs called parameters and return a result. Functions help avoid repetition and make programs easier to test and maintain.

A widely used open-source server-side scripting language designed for building dynamic web pages. PHP code runs on the web server, can connect to databases, and sends generated HTML to the browser.

Programming that executes on the web server before a page is sent to the browser, allowing access to databases, files, and user sessions. The browser receives only the resulting output, not the source code.

A way for a server-side application to remember a user's data across multiple page requests, usually by storing a session identifier in a cookie. It is commonly used to keep users logged in while they browse.

A small piece of data that a website stores in the user's browser and sends back with later requests. Cookies remember preferences or login state, but they can also raise privacy concerns when used for tracking.

The standard language for defining, querying, and modifying data in relational databases. Common statements include SELECT to retrieve rows, INSERT to add them, and UPDATE to change existing values.

A column or set of columns whose value uniquely identifies each row in a table and can never be null or duplicated. It enforces entity integrity and is often used to link tables together.

A column in one table that refers to the primary key of another table, creating a relationship between the two. It enforces referential integrity so that related records cannot point to nonexistent rows.

The buying and selling of goods or services over the internet, including online retail, electronic payments, and digital delivery. Common models are business-to-consumer, business-to-business, and consumer-to-consumer.

A service that securely authorises and processes online card or net-banking payments between a customer, merchant, and bank. It encrypts transaction details and returns a success or failure result to the shopping site.

The practice of protecting computers, networks, and data from unauthorised access, damage, or theft through technology, policies, and user awareness. It covers threats such as malware, phishing, and data breaches.

A fraudulent attempt to obtain sensitive information such as passwords or card numbers by impersonating a trustworthy entity in email, messages, or fake websites. Users are tricked into revealing data or clicking malicious links.

The process of converting readable data into an unreadable form using a key or algorithm so that only authorised parties can decode it. It protects data in transit and at rest from interception or theft.

An attack in which malicious SQL code is inserted through user input fields to manipulate or expose a database. It is prevented by validating input and using parameterised queries instead of building SQL strings directly.

The delivery of computing services such as storage, servers, and software over the internet on a pay-as-you-use basis. Users access resources from providers like AWS or Azure instead of owning physical hardware.

A network of physical devices embedded with sensors and software that collect and exchange data over the internet. Examples include smart meters, fitness bands, and connected home appliances.