Step 1: Understanding the Concept:
Python uses reserved keywords to signal the start of specific code structures. For functions, a short keyword is used.
Step 2: Detailed Explanation:
- In Python, a function is defined using the def keyword.
- Syntax: \( def \ function\_name(parameters): \)
- Other languages use different keywords: Javascript uses 'function', while C/C++ uses the return type as the starting point. Python's 'def' stands for 'define'.
Step 3: Final Answer:
The correct keyword is def.