Table of Contents
This glossary collects short, beginner-friendly definitions of terms used throughout the course. Use it as a quick reference while you learn and practice.
A
algorithm
A step-by-step set of instructions for solving a problem or completing a task.
API (Application Programming Interface)
A defined way for different programs or parts of programs to talk to each other and exchange data.
argument
A value you pass into a function when you call it, for example print("Hello") passes "Hello" as an argument.
arithmetic operator
A symbol that performs math operations, such as +, -, , /, //, %, *.
assignment
Storing a value in a variable using =, for example x = 10.
automation
Using programs to perform tasks automatically, with little or no human action.
B
boolean (bool)
A data type that has only two possible values: True or False.
bug
A mistake or problem in a program that causes it to behave incorrectly or crash.
C
class
A blueprint for creating objects. It defines what data (attributes) and actions (methods) the objects will have.
CLI (Command Line Interface)
A text-based way of interacting with the computer by typing commands, like the terminal or Command Prompt.
comment
Text in code that Python ignores, used to explain what the code does. In Python, starts with #.
comparison operator
An operator that compares two values and returns True or False, such as ==, !=, <, >, <=, >=.
condition
An expression that is either True or False, often used in if statements and loops.
console
Another word for a terminal or command line window where you can run Python and see output.
constant (informal)
A variable whose value is meant to stay the same during the program (by convention written in ALL_CAPS), e.g. PI = 3.14159. Python does not strictly enforce this.
D
data type
A category of values, such as int, float, str, bool, list, which determines what you can do with those values.
data structure
A way of organizing and storing data, such as lists, tuples, dictionaries, and sets.
data visualization
Showing data using charts or graphs to make it easier to understand.
debugging
Finding and fixing bugs (errors or problems) in your code.
dictionary (dict)
A collection of key–value pairs, for example {"name": "Alice", "age": 30}.
E
error (exception)
A problem that happens while running a program, such as dividing by zero or using an undefined variable.
expression
A piece of code that produces a value, like 2 + 3, x * 10, or "Hi" + "!".
F
file path
A string that describes where a file is located on your computer, e.g. "C:\\Users\\me\\file.txt" or "/home/me/file.txt".
float
A number with a decimal point, such as 3.14 or 0.5.
for loop
A loop that repeats code a specific number of times or over items in a sequence, like for x in range(5):.
function
A named block of code that performs a specific task and can be reused, defined with def.
G
GUI (Graphical User Interface)
A visual way to interact with programs using windows, buttons, icons, and so on.
H
hard‑coded
Values written directly into the code instead of being taken from input, a configuration, or a variable.
I
IDE (Integrated Development Environment)
A program that helps you write code, often with features like syntax highlighting, auto-complete, and debugging tools.
IDLE
The simple IDE that comes with Python. It lets you write and run Python code.
import
Bringing in code from a module or library so you can use it in your own program, using the import statement.
indentation
Spaces at the beginning of a line of code. In Python, indentation defines blocks of code (for example inside if, for, while, and functions).
int (integer)
A whole number without a decimal point, like -3, 0, or 42.
interactive mode
Using Python in a way where you type commands and see results immediately, such as the Python REPL.
L
library
A collection of pre-written code you can reuse, often grouped into modules, such as math, random, or external packages.
list
An ordered, changeable collection of values, written in square brackets, e.g. [1, 2, 3].
literal
A value written directly in code, such as 10, 3.14, "hello", or [1, 2, 3].
loop
A structure that repeats a block of code multiple times, like for or while.
M
method
A function that belongs to an object (or class) and is called using dot notation, e.g. "hello".upper().
module
A Python file that contains code (functions, classes, variables) you can import and use in another file.
N
None
A special value in Python that means “no value” or “nothing here”.
NumPy
A popular Python library for efficient numerical computing and working with arrays of numbers.
O
object
An instance of a class; a specific “thing” created from a class blueprint.
object‑oriented programming (OOP)
A way of organizing programs around objects and classes instead of just functions and data.
operator
A symbol that performs an operation on values or variables, such as +, -, *, /, ==, and, or.
P
package
A collection of related modules, often installed with pip.
parameter
A variable name listed in a function definition; it receives the value (argument) passed to the function.
pandas
A Python library for working with structured data, such as tables and spreadsheets.
pip
Python’s package manager. It installs and manages external libraries.
print
A built-in function that displays text or values on the screen.
program
A set of instructions written in a programming language that tells a computer what to do.
Python interpreter
The program that reads and executes Python code.
R
range
A built-in function that generates a sequence of numbers, often used in for loops.
read–eval–print loop (REPL)
An interactive environment where you type code, Python evaluates it, and prints the result immediately (the Python prompt).
return value
The value that a function sends back to the code that called it, using the return keyword.
S
scope
The part of the program where a variable can be accessed (for example, inside a function vs. in the whole file).
script
A Python file (.py) containing code that can be run as a program.
set
An unordered collection of unique elements, like {1, 2, 3} (no duplicates).
shell / terminal
A text-based program where you can type commands to control the computer and run Python.
standard library
The collection of modules that come with Python, such as math, random, and datetime.
statement
A complete instruction in Python, such as x = 5, print(x), or an if block header.
string (str)
Text data in Python, usually written inside quotes, e.g. "hello" or 'world'.
syntax
The rules for how code must be written so the interpreter can understand it.
T
traceback
The detailed error message Python shows when an exception occurs, telling you where the error happened.
tuple
An ordered collection of values that cannot be changed (immutable), written in parentheses, e.g. (1, 2, 3).
type
The kind of value (like int, float, str, bool, etc.). The built-in type() function shows you an object’s type.
U
variable
A named place in memory that stores a value, for example name = "Sam".
virtual environment (venv)
An isolated Python environment where you can install packages without affecting other projects.
W
while loop
A loop that keeps running as long as a condition is True.
whitespace
Spaces, tabs, and newlines. In Python, whitespace (especially indentation) affects how code is grouped.
wrapper (function or library)
Code that provides a simpler or more convenient way to use other code or an external system.
Symbols and Special Names
__init__ method
A special method in a class that runs when a new object is created; used to set up the object’s initial state.
==
Comparison operator that checks whether two values are equal.
=
Assignment operator that gives a value to a variable.
if, elif, else
Keywords used for conditional branching based on True/False conditions.
and, or, not
Logical operators used to combine or modify boolean expressions.
break
Keyword that immediately exits the nearest loop.
continue
Keyword that skips the rest of the current loop iteration and moves to the next one.
try, except
Keywords used to handle (catch) errors so your program can keep running or fail more gracefully.
f-string
A string with an f in front (like f"Hello {name}") that lets you insert variables and expressions inside {}.