Comment by dspillett

You are conflating two similar but different UI elements.

A popup is a larger object, often a full window, that covers large parts of other elements or sometimes the entire screen. They are sometimes modal.

A toast is a smaller element, appearing (often by sliding into view upwards, hence the cutesy name) in or above a specific notification area of the application or the overall OS. These are much smaller, seldom modal and often convey useful notifications or warnings, unlike popups (especially modal ones) that are often either useless or actively, deliberately, in the way.

While it is correct to call then both popups if you wish, "toasts" are generally considered a specific subset.