oncevisible
oncevisible is a term used to describe an object or entity that, after being observed or detected, subsequently becomes imperceptible or undetectable. This can occur for various reasons, including the object moving out of the range of observation, becoming obscured, or ceasing to emit any detectable signals. The concept is often encountered in fields like physics, astronomy, and surveillance, where the disappearance of a target is a critical event.
In astronomy, for instance, a celestial body might be oncevisible if it passes behind another object, enters