Source code
The source code of a computer program (or software) is a set of lines of text with the steps that the computer must follow to execute a loader.
The source code of a program is written by a programmer in some human-readable programming language, usually in the form of plain text. However, the program written in a human-readable language is not directly executable by the computer in its first state, but must be translated into another language or binary code; this way it will be easier for the machine to interpret it (machine language or object code that can be executed by the computer hardware). For this translation, so-called compilers, assemblers, interpreters and other translation systems are used.
The term source code is also used to refer to the source code of other pieces of software, such as the source code of a web page, which is written in HTML markup language or Javascript, or other languages web programming, and which is subsequently executed by the web browser to display said page when it is visited.
The area of computing that is dedicated to the creation of programs, and therefore to the creation of their source code, is software engineering.
Licenses
An interesting thing to consider when talking about the source code of a computer program is whether its license allows that source code to be made available for anyone to study, modify, or reuse. When this aspect is fulfilled, it is said that the program is open source and they are, in general, free software, as opposed to proprietary software for which none of these permissions are granted.