How is a dictionary defined in Python?

A dictionary in Python is defined using curly braces with key-value pairs. This structure allows for the creation of a collection of key-value pairs, where each key is unique, and it is used to retrieve the associated value efficiently. For example, you can define a dictionary like this: my_dict = {"name": "Alice", "age": 30}.

The use of curly braces is significant because it visually distinguishes dictionaries from other data types in Python. Square brackets are used for lists, while parentheses are for tuples. Angle brackets are not a standard syntax for any built-in data structure in Python. Understanding this distinction is crucial for correctly utilizing dictionaries within Python for data storage and manipulation tasks.