Software is a collection of instructions and data that tell the computer how to work. This is in contrast to physical hardware, from which the system is built and actually performs the work. In computer science and software engineering, computer software is all information processed by computer systems, including programs and data. Computer software includes computer programs, libraries and related non-executable data, such as online documentation or digital media. Computer hardware and software require each other and neither can be realistically used on its own.

A computer programmer, sometimes called a software developer, a programmer or more recently a coder, is a person who creates computer software. The term computer programmer can refer to a specialist in one area of computers, or to a generalist who writes code for many kinds of software.

Computer security software or cybersecurity software is any computer program designed to influence information security. This is often taken in the context of defending computer systems or data, yet can incorporate programs designed specifically for subverting computer systems due to their significant overlap, and the old adage that the best defense is a good offense.

Application software is computing software designed to carry out a specific task other than one relating to the operation of the computer itself, typically to be used by end-users. Examples of an application include a word processor, a spreadsheet program, an accounting application, a web browser, an email client, a media player, a console game, or a photo editor. The collective noun application software refers to all applications collectively. The other principal classifications of software are system software, relating to the operation of the computer, and utility software ("utilities").

Software engineering is the systematic application of engineering approaches to the development of software.

A software engineer is a person who applies the principles of software engineering to the design, development, maintenance, testing, and evaluation of computer software.

Computer-aided design (CAD) is the use of computers to aid in the creation, modification, analysis, or optimization of a design. CAD software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing. Designs made through CAD software are helpful in protecting products and inventions when used in patent applications. CAD output is often in the form of electronic files for print, machining, or other manufacturing operations. The term CADD is also used.

Computer science is the study of algorithmic processes, computational machines and computation itself. As a discipline, computer science spans a range of topics from theoretical studies of algorithms, computation and information to the practical issues of implementing computational systems in hardware and software.

Advanced Computer Software Group Ltd. is a Private British company founded by Vin Murria in 2008 with its main headquarters based in Slough, Berkshire. It provides Information Technology services including hosting and cloud based systems to the NHS and many other organisations. Through various acquisitions, in 2016 it became the third largest software provider in the UK market while employing over 2,000 people with a customer base of more than 20,000 organisations. Later in the year it would go on to rebrand itself to "Advanced" while opening a new central headquarters in Birmingham's Mailbox.

A software bug is an error, flaw or fault in a computer program or system that causes it to produce an incorrect or unexpected result, or to behave in unintended ways. The process of finding and fixing bugs is termed "debugging" and often uses formal techniques or tools to pinpoint bugs, and since the 1950s, some computer systems have been designed to also deter, detect or auto-correct various computer bugs during operations.

A software patent is a patent on a piece of software, such as a computer program, libraries, user interface, or algorithm.

A computer virus is a type of computer program that, when executed, replicates itself by modifying other computer programs and inserting its own code. If this replication succeeds, the affected areas are then said to be "infected" with a computer virus.

Computer-aided software engineering (CASE) is the domain of software tools used to design and implement applications. CASE tools are similar to and were partly inspired by computer-aided design (CAD) tools used for designing hardware products. CASE tools are used for developing high-quality, defect-free, and maintainable software. CASE software is often associated with methods for the development of information systems together with automated tools that can be used in the software development process.

Computer engineering is a branch of engineering that integrates several fields of computer science and electronic engineering required to develop computer hardware and software. Computer engineers usually have training in electronic engineering, software design, and hardware-software integration instead of only software engineering or electronic engineering. Computer engineers are involved in many hardware and software aspects of computing, from the design of individual microcontrollers, microprocessors, personal computers, and supercomputers, to circuit design. This field of engineering not only focuses on how computer systems themselves work but also how they integrate into the larger picture.

Installation of a computer program, is the act of making the program ready for execution. Installation refers to the particular configuration of a software or hardware with a view to making it usable with the computer. A soft or digital copy of the piece of software (program) is needed to install it. There are different processes of installing a piece of software (program). Because the process varies for each program and each computer, programs often come with an installer, a specialised program responsible for doing whatever is needed for the installation. Installation may be part of a larger software deployment process.

Free software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, not price: all users are legally free to do what they want with their copies of a free software regardless of how much is paid to obtain the program. Computer programs are deemed "free" if they give end-users ultimate control over the software and, subsequently, over their devices.

Antivirus software, or anti-virus software, also known as anti-malware, is a computer program used to prevent, detect, and remove malware.

Proprietary software, also known as non-free software, is computer software for which the software's publisher or another person reserves some rights from licensees to use, modify, share modifications, or share the software. It sometimes includes patent rights.