In the context of programming languages, compilation refers to the process of translating source code written in a high-level programming language into a lower-level representation, typically machine code or bytecode, that can be executed directly by a computer.

The compilation process involves several steps:

1. Lexical Analysis: The source code is divided into tokens, which are the smallest meaningful units of the programming language, such as keywords, identifiers, operators, and literals. This step is performed by a component called a lexer or tokenizer.
2. Syntax Analysis: The tokens are analyzed based on the language’s syntax rules to form a hierarchical structure known as the Abstract Syntax Tree (AST). The syntax analysis is done by a parser, which checks if the code adheres to the grammar of the programming language.
3. Semantic Analysis: The AST is traversed to perform semantic checks and build a symbol table. This phase verifies the correctness of the code’s meaning, such as type checking, scoping rules, and variable declarations.
4. Intermediate Code Generation: In some cases, an intermediate representation of the code is generated. This intermediate code is closer to the target machine code but still independent of any specific hardware or operating system.
5. Optimization: The intermediate representation is analyzed and transformed to improve the code’s efficiency and performance. Various optimization techniques, such as constant folding, loop unrolling, and dead code elimination, may be applied at this stage.
6. Code Generation: Finally, the compiler generates the target machine code or bytecode from the optimized intermediate representation. This code is specific to the target hardware or virtual machine on which the program will run.

Once the compilation process is complete, the resulting executable file or bytecode can be executed directly by the computer or interpreted by a runtime environment, depending on the language and the compilation strategy used.

It’s important to note that not all programming languages use traditional compilation. Some languages, like JavaScript or Python, use an interpreter to execute the code directly without a separate compilation step. These languages typically perform a just-in-time (JIT) compilation or interpretation of the source code during runtime.