Polling is the action of waiting until a condition has changed. This is usually within the context of I/O operations, like checking if an API has answered. There are multiple ways to poll for results.
One particularly wasteful form of polling is busy waiting.
Non-testable
Busy-waiting is effectively the only kind of polling mentioned in CPSC 213, but there are other forms of polling that are widely used (and not nearly as wasteful). Node.js for example uses a form of polling called event loop polling.