Final answer:
The Update function is called every frame in a game's lifecycle to handle events like input detection and game logic updates, distinguishing it from other functions which have specific and different triggers.
Step-by-step explanation:
The function described in your question is most akin to the Update function. This is a core concept in game development where the Update function is called once per frame in the game's lifecycle. It allows for the handling of non-physics related events such as detecting user inputs, updating the game logic, and animating characters or objects. In contrast to the other functions listed, Start is called only once at the beginning, FixedUpdate is often used for physics-related updates at fixed intervals, and OnCollisionEnter is invoked when a collision is detected.