An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer. The word is used in astronomy (see below). It can also refer to any situation wherein an object in the foreground blocks from view (occults) an object in the background. In this general sense, occultation applies to the visual scene observed from low-flying aircraft (or computer-generated imagery) wherein foreground objects obscure distant dynamically, as the scene changes over time.

An occultation occurs when an apparently larger body passes in front of an apparently smaller one. A transit occurs when an apparently smaller body passes in front of an apparently larger one. In the combined case where the smaller body regularly transits the larger object, an occultation is also termed a secondary eclipse.

An eclipse occurs when a body disappears or partially disappears from view, either by an occultation, as with a solar eclipse, or by passing into the shadow of another body, as with a lunar eclipse (thus both are listed on NASA's eclipse page).