Skip to main content

Python Glossary - A-Z Reference 📚

A comprehensive reference of Python programming terms. Each term includes a clear definition and links to relevant tutorial pages for deeper learning.

A-C​

Argument — A value passed to a function when calling it. Arguments are assigned to the function's parameters. See Functions.

Boolean — A data type with two values: True and False. Used in conditionals and logical operations. See Booleans.

Break — A statement that exits a loop prematurely. When executed inside a for or while loop, it stops the loop immediately. See Break/Continue/Pass.

Class — A blueprint for creating objects. Classes define attributes and methods that instances of the class will have. See Classes & Objects.

Comment — Text in code that is ignored by the interpreter. Comments start with # and are used to explain code. See Syntax & Comments.

Comprehension — A concise syntax for creating sequences (lists, dicts, sets) from iterables. E.g., [x**2 for x in range(10)]. See List Comprehension.

Constructor — A special method __init__() that is called when an object is created from a class. It initializes the object's attributes. See Constructors.

Continue — A statement that skips the rest of the current loop iteration and moves to the next one. See Break/Continue/Pass.

D-F​

Dictionary — A mutable, unordered collection of key-value pairs. Created with {} or dict(). Keys must be immutable. See Dictionaries.

Docstring — A string literal that appears as the first statement in a function, class, or module. Used for documentation. Enclosed in triple quotes """...""".

Exception — An event that disrupts normal program flow. Raised by errors (e.g., ZeroDivisionError, TypeError) and can be handled with try/except. See Exceptions.

File — An object representing a file on disk. Python provides built-in functions like open() to read from and write to files. See File Handling.

Float — A data type representing floating-point numbers (numbers with decimal points). E.g., 3.14, -0.5. See Numbers & Casting.

Function — A reusable block of code defined with def. Functions take arguments, perform actions, and can return values. See Functions.

G-I​

Generator — A function that uses yield instead of return to produce a sequence of values lazily. Generators are memory-efficient for large datasets. See Decorators & Generators.

IDLE — Python's built-in Integrated Development and Learning Environment. A simple IDE that comes bundled with Python installations.

Import — A statement that brings modules or specific objects from modules into the current namespace. E.g., import math, from sys import argv. See Modules.

Inheritance — An OOP concept where a class derives attributes and methods from a parent class. Enables code reuse and hierarchical relationships. See Inheritance.

Integer — A whole number data type (positive, negative, or zero). E.g., 42, -7, 0. See Numbers & Casting.

Interpreter — The program that executes Python code line by line. Python is an interpreted language; the interpreter reads, compiles, and runs code. See What is Python?.

Iterable — Any Python object that can be looped over with a for loop. Examples include lists, strings, tuples, dicts, and files. Implements the __iter__() or __getitem__() method.

J-L​

Lambda — A small anonymous function defined with the lambda keyword. Can take any number of arguments but has only one expression. E.g., lambda x: x * 2. See Lambda Functions.

List — An ordered, mutable collection of items. Created with [] or list(). Lists can contain mixed data types and support indexing, slicing, and methods like append(), pop(). See Lists.

Loop — A construct that repeats a block of code. Python has for loops (iterate over sequences) and while loops (repeat while a condition is true). See Loops.

M-O​

Method — A function that belongs to an object or class. Methods are called on instances (e.g., "hello".upper()) or on the class itself (e.g., classmethod). See Classes & Objects.

Module — A file containing Python definitions and statements. Modules allow you to organize code into reusable files. Imported using the import statement. See Modules.

Mutability — Whether an object's value can be changed after creation. Mutable types: list, dict, set. Immutable types: int, float, str, tuple, frozenset. See Variables & Data Types.

Namespace — A container that maps names to objects. Each module, function, and class has its own namespace. The LEGB rule (Local, Enclosing, Global, Built-in) determines name resolution order.

None — A special constant representing the absence of a value. Its type is NoneType. Often used as a default return value or to signify "no result."

Object — The fundamental building block in Python. Everything in Python is an object: numbers, strings, functions, classes. Objects have attributes and methods.

Operator — A symbol that performs an operation on values. Categories include arithmetic (+, -, *), comparison (==, <, >), logical (and, or, not), and assignment (=, +=). See Operators.

P-R​

Package — A collection of related modules organized in directories. A directory must contain an __init__.py file to be treated as a package. See Packaging.

Parameter — A variable listed in a function's definition that receives an argument when the function is called. Parameters are placeholders; arguments are the actual values. See Functions.

PIP — Python's package installer. Used to install third-party packages from the Python Package Index (PyPI). E.g., pip install requests.

REPL — Read-Eval-Print Loop. Python's interactive shell where you type commands and see results immediately. Access by running python without a script.

Return — A statement that exits a function and optionally sends a value back to the caller. A function without an explicit return returns None.

S-U​

Set — An unordered collection of unique elements. Created with {} or set(). Supports mathematical operations like union, intersection, and difference. See Sets.

Slice — A syntax for extracting a portion of a sequence. Written as sequence[start:stop:step]. E.g., "hello"[1:4] returns "ell".

Statement — A unit of code that Python can execute. Examples: assignment (x = 5), if statements, for loops, import statements.

Str — The string data type representing text. Strings are immutable sequences of Unicode characters. Created with single quotes, double quotes, or triple quotes. See Strings.

Syntax — The set of rules that defines how Python code must be written. Python uses indentation to define blocks, unlike curly braces in other languages. See Syntax & Comments.

Tuple — An ordered, immutable collection of items. Created with () or tuple(). Often used for fixed collections of values. See Tuples.

Type — The classification of data in Python. Determines what operations can be performed on a value. Use type() to check an object's type. See Variables & Data Types.

V-Z​

Variable — A name that references a value stored in memory. In Python, variables are created by assignment and do not require explicit type declaration. See Variables & Data Types.

Virtual Environment — An isolated Python environment that allows you to manage dependencies for different projects separately. Created with python -m venv myenv.

While — A loop that continues executing as long as its condition evaluates to True. Use when the number of iterations is not known in advance. See Loops.

With — A statement used for resource management. Ensures that resources (files, network connections) are properly cleaned up after use. See File Handling.

Zen of Python — A collection of 19 guiding principles for Python design. Written by Tim Peters. Access it by typing import this in the Python interpreter.

🔗 Related Resources​

Master these terms and you will speak Python fluently. Bookmark this page for quick reference!