Tamil Nadu HSE Second Year Computer Science key terms

Raw, unprocessed facts and figures such as marks, names or temperatures that on their own carry little meaning until they are organised or interpreted.

Data that has been processed, organised or summarised so it becomes meaningful and useful for decision making, for example an average mark or a total sales figure.

A base-2 positional number system that uses only the digits 0 and 1, where each place value is a power of two; it is the internal representation used by digital computers.

A base-16 number system using digits 0-9 and letters A-F, widely used as a short, readable way to write long binary patterns such as memory addresses and colour codes.

The smallest unit of digital information, representing a single binary digit that is either 0 or 1, and the building block of all data stored in a computer.

A group of eight bits treated as one unit; it can store one ASCII character or a small integer value, and is the standard unit for measuring memory and storage capacity.

A method of representing signed integers in binary in which the leftmost bit holds the sign, and negative values are formed by inverting all bits and adding one.

A branch of mathematics dealing with variables that take only the values true and false, using operators AND, OR and NOT; it underlies the design of logic gates and digital circuits.

A basic electronic circuit that performs a Boolean operation on one or more binary inputs to produce a single output, such as an AND gate, OR gate or NOT gate.

A linear data structure in which insertion and deletion both happen at one end called the top, following last-in-first-out order, like a pile of plates.

A linear data structure in which elements are inserted at the rear and removed from the front, following first-in-first-out order, like people standing in a ticket line.

The act of adding a new element onto the top of a stack; it increases the stack size by one and can fail if the stack is already full.

The act of removing and returning the element at the top of a stack; it decreases the stack size by one and fails if the stack is empty.

The operation of inserting a new element at the rear end of a queue, increasing its length by one; it cannot be done when the queue is full.

The operation of removing and returning the element at the front of a queue, decreasing its length by one; it cannot be done when the queue is empty.

A queue implemented so that the last position wraps around to the first, allowing freed space at the front to be reused and avoiding the wasted cells of a simple array queue.

A collection of nodes where each node stores data plus a reference to the next node, so elements need not occupy consecutive memory locations and can grow or shrink easily.

A single unit of a linked structure that holds one data value together with one or more links pointing to related nodes, such as the next node in a list.

A blueprint or template in object-oriented programming that defines the attributes and methods its objects will have, without itself holding any object's data.

A concrete instance created from a class, with its own copy of the attributes and access to the methods defined by that class.

A special method that runs automatically when an object is created, used to initialise the object's attributes; in Python it is written as init.

A feature in which a new class derives attributes and methods from an existing class, promoting code reuse and allowing the child class to extend or override behaviour.

The ability of the same operation or method name to behave differently depending on the object or arguments involved, for example the same draw method acting differently for different shapes.

The bundling of data and the methods that operate on it inside one class, with access restricted through naming conventions or property methods to protect internal state.

A column or set of columns chosen to uniquely identify each row in a table; it must be unique for every row and cannot contain a null value.

A column or set of columns in one table that refers to the primary key of another table, enforcing referential integrity between related tables.

Any column or minimal combination of columns that can uniquely identify a row in a table; one of these is selected to become the primary key.

A database rule ensuring that every value in a foreign key column matches an existing value in the referenced primary key, or is null, so relationships stay consistent.

The step-by-step process of organising tables to reduce redundant data and avoid insertion, deletion and update anomalies, typically through first, second and third normal forms.

Structured Query Language, the standard language for creating, querying and modifying relational databases, including commands such as SELECT, INSERT, UPDATE and DELETE.

A unique numeric label assigned to a device on a network so data can be routed to it; IPv4 uses four octets while IPv6 uses a much longer hexadecimal form.

The Domain Name System, a distributed naming service that translates human-friendly domain names such as example.com into the numeric IP addresses computers use.

An agreed set of rules governing how data is formatted, transmitted and acknowledged between devices, for example TCP for reliable delivery and HTTP for web pages.

A Uniform Resource Locator, the address that identifies the location of a resource on the web, made up of a protocol, domain name and optional path.

HyperText Markup Language, the standard language of tags used to structure web page content such as headings, paragraphs, lists, links and images.

Cascading Style Sheets, a language of rules used to control the presentation of HTML documents, including colours, fonts, spacing, layout and responsive behaviour.

A scripting language that runs in the browser to make web pages interactive, handling events, validating forms and updating content without reloading the page.

The part of a CSS rule that specifies which HTML elements the declaration block applies to, such as a tag name, a class name or an id.

The Document Object Model, a tree-shaped representation of an HTML page that scripts can read and modify to add, change or remove elements dynamically.

A programming technique that catches runtime errors using try, except and finally blocks so that a program can respond gracefully instead of crashing.

A Python object returned by the open function that provides methods such as read, write and close for working with data stored on disk.

A finite, ordered set of unambiguous steps that solves a problem or completes a task, and which must terminate after a limited number of operations.

A diagram that represents an algorithm using standard symbols such as ovals for start and stop, parallelograms for input and output, and diamonds for decisions.

A structured, English-like description of an algorithm that uses programming constructs such as IF, WHILE and READ without following the strict syntax of any language.

Presenting another person's words, code or ideas as one's own without proper credit, a serious breach of academic and professional computing ethics.

The legal right of a creator to control copying, distribution and adaptation of an original work, including software and digital content, for a defined period.