Final answer:
Callback hell refers to the difficulty of managing and maintaining deeply nested callback functions in JavaScript, making the code hard to read.
Step-by-step explanation:
Callback hell refers to the difficulty of managing and maintaining deeply nested callback functions, making the code hard to read. It is a term commonly used in JavaScript development, especially when dealing with asynchronous code. In a situation of callback hell, multiple asynchronous operations are executed one after the other in nested callback functions, leading to complex and hard-to-follow code.