Is making up for something the act of doing it out of its prescribed time? What is the meaning of making up for missed fasts, and does it differ from making up for missed prayers? If so, what are the differences?

"Qada'" (making up) according to jurists is performing an act of worship after its designated time, whether the time was extended or limited. This clarifies the meaning of "faqdu" (then make them up) in the Hadith (definition). As for fasting, "qada'" is performing the fast after Ramadan (definition) for those who were unable to perform it during Ramadan due to an excuse. And making up a prayer is performing it after its necessary time has expired.