Invisibility is the state of an object that cannot be seen. An object in this state is said to be invisible (literally, “not visible”). The term is often used in fantasy/science fiction, where objects cannot be seen by magical or technological means; however, its effects can also be demonstrated in the real world, particularly in physics and perceptual psychology classes.
Since objects can be seen by light in the visible spectrum from a source reflecting off their surfaces and hitting the viewer’s eye, the most natural form of invisibility (whether real or fictional) is an object that neither reflects nor absorbs light (that is, it allows light to pass through it). This is known as transparency, and is seen in many naturally occurring materials (although no naturally occurring material is 100% transparent).
Invisibility perception depends on several optical and visual factors. For example, invisibility depends on the eyes of the observer and/or the instruments used. Thus an object can be classified as “invisible to” a person, animal, instrument, etc. In research on sensorial perception it has been shown that invisibility is perceived in cycles.
Invisibility is often considered to be the supreme form of camouflage, as it does not reveal to the viewer any kind of vital signs, visual effects, or any frequencies of the electromagnetic spectrum detectable to the human eye, instead making use of radio, infrared or ultraviolet wavelengths.
In illusion optics, invisibility is a special case of illusion effects: the illusion of free space.
Impossible to defeat, destroy or kill; too powerful to be defeated or overcome.
Someone or something that cannot be defeated, destroyed or killed.
Unable to be seen; out of sight; not visible.
Not appearing on the surface.
Apparently, but not actually, offline.
“I went invisible so that my ex-girlfriend wouldn’t send me instant messages.”
That is ignored by a person.
To make invisible, to invisiblize.
An invisible person or thing; specifically, God, the Supreme Being.
A Rosicrucian; so called because avoiding declaration of his craft.
One of those (as in the 16th century) who denied the visibility of the church.