A programming language is a formal language comprising a set of instructions that produce various kinds of output. They are used in computer programming to implement algorithms and manipulate data. Programming languages are the primary tools for creating software, websites, apps, and other digital technologies.

High-Level Languages: These are closer to human languages and further from machine code. They are more abstract, easier to learn, and more user-friendly. Examples include Python, Java, and C++.

Low-Level Languages: These include assembly language and machine code, which are closer to the hardware. They offer greater control over hardware components but are more complex and harder to learn.

Syntax: This is the set of rules that defines the combinations of symbols that are considered to be correctly structured programs in that language. For instance, Python uses indentation to define blocks of code.

Semantics: This refers to the meaning of the symbols, characters, and words in a programming language. It's what makes the code meaningful and functional.

Compiled vs. Interpreted: Some languages are compiled, meaning the code is translated into machine code before execution. Others are interpreted, where the code is executed line-by-line by an interpreter. Python, for instance, is an interpreted language.

Python: Known for its simplicity and readability, Python is widely used in web development, data analysis, artificial intelligence, and scientific computing.

Java: A highly popular language known for its portability across platforms, commonly used in mobile app development (especially Android apps), and enterprise-level applications.

JavaScript: Essential for web development, JavaScript is used to create interactive and dynamic elements on web pages.

C++: Known for its performance and efficiency, C++ is often used in system/software development, game development, and applications requiring real-time processing.

HTML/CSS: Although not programming languages in the traditional sense, HTML (HyperText Markup Language) and CSS (Cascading Style Sheets) are crucial for web design and layout.

Python's simplicity and readability make it an excellent choice for beginners. Its vast array of libraries and frameworks allows for application in numerous fields, from web development with Django to machine learning with TensorFlow. Python’s community support and open-source nature also mean that beginners have access to a wealth of resources and learning materials. This versatility and ease of use make Python a top choice for those looking to apply programming across various disciplines.