Name of the spinning load/wait/buffer animation

The term you heard was most likely Throbber - this is from early web browsers (Mosaic, Netscape) where the page load indicator was indicated by animating the browser logo.

In Android development they're called "indeterminate progress bars."

In iOS development they're called "activity indicators."

Another common term is "spinner", e.g., STYLE_SPINNER in ProgressDialog, but care should be taken to avoid confusion with spinner-style menus.