What does loading spinner mean?
A Loading Spinner in PowerApps is an animated element that helps to indicate loading is in process. When the loading data is slow, that case, the loading spinner will appear. This means, it hleps to let the user know that the process is in busy mode and it may be take some time to appear something.
What is a spinner in UI?
A spinner is an animated element that appears after a user's action to indicate that saving or loading is in progress. Implementation (Vue.js)