Tamil Nadu HSE First Year Computer Applications key terms

A base-2 way of writing numbers that uses only the digits 0 and 1, where each position stands for a power of two. Computers store and process all data in this form.

The smallest unit of digital data, holding a single value of either 0 or 1. Groups of bits combine to represent characters, numbers, and instructions inside a computer.

A group of eight bits treated as one unit. It commonly stores one character, and larger amounts of memory are measured in kilobytes, megabytes, and gigabytes built from bytes.

The process of changing a base-10 number into its base-2 equivalent by repeatedly dividing by two and reading the remainders in reverse order.

A base-8 number system using the digits 0 to 7. Each octal digit corresponds to exactly three binary bits, so it is used as a short way to write binary values.

A base-16 number system using digits 0 to 9 and letters A to F. One hexadecimal digit stands for four binary bits, making it a compact notation for memory addresses and colour codes.

American Standard Code for Information Interchange, a character code that assigns a number from 0 to 127 to letters, digits, punctuation, and control characters so computers can store and exchange text.

A universal character encoding standard that assigns a unique code point to characters of most of the world's writing systems, including Tamil, so text can be represented consistently across software and platforms.

The Central Processing Unit is the part of a computer that fetches, decodes, and executes instructions and performs arithmetic and logic operations. It is often called the brain of the computer.

The Arithmetic Logic Unit is the section of the CPU that carries out arithmetic operations such as addition and subtraction and logical operations such as comparison and AND, OR, NOT.

The CPU component that directs the flow of data and instructions, telling other units what to do and when. It decodes each instruction and generates the signals that carry it out.

Memory the CPU accesses directly, such as RAM and ROM. It holds programs and data currently in use, is fast, and in the case of RAM loses its contents when power is switched off.

Random Access Memory is the read-write working memory of a computer. Any location can be accessed directly, and its contents are erased when the computer is switched off.

Read Only Memory is non-volatile memory whose contents are written during manufacture and normally cannot be changed by the user. It stores firmware such as the start-up instructions used when a computer is switched on.

Non-volatile devices such as hard disks, pen drives, and optical discs that keep data permanently when power is off. They are slower than main memory but hold far larger amounts of data.

System software that manages hardware resources, runs application programs, and provides a user interface. Examples include Windows, Linux, and Android, which let users and programs interact with the machine.

A Graphical User Interface lets users work with a computer through windows, icons, menus, and a pointer instead of typed commands. It makes software easier to learn and use.

A way of interacting with a computer by typing text commands at a prompt. It is powerful and scriptable but requires users to remember command names and their syntax.

Software whose source code is released so anyone may study, modify, and redistribute it, often under licences such as the GNU General Public License. Examples include Linux and LibreOffice.

Small programs that help maintain and protect a computer system, such as antivirus tools, disk cleanup, backup, and file compression utilities. They support the operating system rather than doing user production work.

A word processor feature that automatically moves text to the next line when the current line is full, so the user does not press Enter at the end of every line.

The setting that controls how text lines up between the left and right margins: left, right, centre, or justified. It affects the appearance of a whole paragraph rather than single characters.

A word processing command that searches a document for a piece of text and substitutes another, either one occurrence at a time or all at once, saving effort in long documents.

A feature that combines a main document with a data source, such as a list of names and addresses, to produce many personalised copies like letters, labels, or certificates.

Areas at the top and bottom of each page that repeat the same content, such as a title, page number, or date. They keep documents consistent and professional.

The address of a worksheet cell, formed from its column letter and row number, such as B5. References are used in formulas to point to the data being calculated.

An expression entered in a spreadsheet cell that begins with an equals sign and calculates a result from values, cell references, and operators, for example =A1+B1*2.

A built-in spreadsheet operation with a name, such as SUM, AVERAGE, or MAX, that takes arguments and returns a value. Functions save time compared with writing long formulas by hand.

A relative reference like A1 changes when a formula is copied to another cell, while an absolute reference like $A$1 stays fixed. The dollar signs lock the column, row, or both.

A graphical representation of worksheet data, such as a bar, pie, or line chart, that makes patterns and comparisons easier to see than a table of numbers alone.

Sorting rearranges rows into order based on one or more columns, while filtering displays only rows that meet a condition. Together they help analyse large data tables quickly.

The visual effect that plays when moving from one slide to the next during a presentation. Transitions apply to whole slides, unlike animations that affect objects on a slide.

An effect applied to individual objects such as text, pictures, or shapes on a slide, controlling how they appear, move, or disappear. It should support the message rather than distract the audience.

A template slide that stores the design, fonts, colours, and placeholder positions used by all slides in a presentation. Editing it updates the look of every slide at once.

A unique numeric address assigned to a device on a network so data can be routed to it, such as 192.168.1.10 in IPv4. It works like a postal address for computers.

A Uniform Resource Locator is the address of a resource on the web, giving the protocol, domain name, and path, for example https://example.com/page. Typing it in a browser requests that page.

A set of agreed rules that governs how data is exchanged between devices, covering formatting, timing, and error handling. TCP/IP and HTTP are common examples on the Internet.

A finite, step-by-step procedure that solves a problem or performs a task, written so that each step is clear and unambiguous. Algorithms can be shown as pseudocode or flowcharts.

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

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 coding.

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

The kind of value a variable can hold, such as integer, float, character, string, or Boolean. The type determines which operations are allowed and how much memory is used.

A statement that stores a value in a variable, often written with an equals sign as in total = total + 1. The expression on the right is evaluated first, then placed in the variable.

A control structure such as if, if-else, or switch that runs a block of code only when a test condition is true, letting a program choose between alternative paths.

A control structure that repeats a block of statements while a condition holds or for a fixed number of times. Common forms are while, for, and do-while loops.

A markup element written between angle brackets, such as

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

Extra information written inside a tag's opening bracket as a name-value pair, such as src="pic.jpg" or href="page.html", which modifies how the element behaves or displays.

The standard skeleton of a web page, made up of the doctype declaration and the html, head, and body elements. The head holds metadata and the body holds visible content.

A clickable piece of text or an image that links to another page, file, or location, created with the anchor tag and its href attribute. Hyperlinks connect documents across the web.

A field or combination of fields that uniquely identifies each record in a table. It cannot contain duplicate or null values 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 so related data stays consistent.

One complete row in a database table, holding all the field values that describe a single entity such as one student or one book. Tables are made up of many records.

A Database Management System is software that stores, retrieves, and manages data in databases, handling security, backup, and concurrent access. Examples include MySQL and Oracle.