Glossary

Quick definitions, A to Z. Terms point to the guide that explains them in context.

Argument — the actual value passed to a function when calling it. See Functions.

Boolean / bool — True or False. Note the capitals.

Dictionary / dict — labeled boxes of data: {"name": "Ada"}. See Variables and Types.

Exception — Python's name for a runtime error. try/except handles expected ones.

Float — a number with a decimal point: 1.65.

Function — a named, reusable chunk of work. Defined with def.

Indentation — leading spaces marking a block of code. Four spaces per level; it's syntax, not style.

Input — input() pauses for keyboard text. Always returns a string.

Integer / int — a whole number: 36.

Interpreter — the program that runs Python code. What you start with the python command.

Iteration — doing something once per item, usually with for.

Library / module — a toolbox of ready-made code. import csv loads one.

List — an ordered collection: ["apple", "banana"]. Counting starts at 0.

None — deliberately empty. Not zero, not "".

Parameter — the placeholder name in a function definition; the caller fills it with an argument.

Scope — where a variable is visible. Variables made inside a function stay inside it.

Script — Python commands saved in a .py file, run top to bottom.

String / str — text in quotes: "hello".

Traceback — the error report Python prints. Read it bottom-up: last line says what, lines above say where.

Tuple — like a list, but unchangeable: (1, 2).

Type — what kind of value something is: text, number, list.

Variable — a named box holding a value: name = "Ada".

Virtual environment — an isolated Python setup per project, so libraries don't clash. (Beyond these guides' scope, but you'll meet the term.)