(linguistics) A kind of comparative sentence that superficially seems acceptable but actually has no clear meaning. Example: "More people have been to Russia than I have."

An optical illusion involving the misperception of the position of one segment of a transverse line that has been interrupted by the contour of an intervening structure.

(aviation) An illusory perception of one's pitch angle, due to the effects of linear acceleration on the vestibular system of the inner ear.

An optical illusion in which an arrangement of horizontal and vertical bars of various lengths may be viewed as either a series of rectangles or a series of circles.

A cognitive bias by which people wrongly think that they have direct insight into the origins of their mental states, while treating other people's introspections as unreliable.

An image that is visually deceptive or misleading.

The optical illusion resulting from the Thatcher effect.

An optical illusion in which parallel lines are made to appear convergent or divergent by means of oblique intersections.

An optical illusion consisting of a stylized arrow whose midpoint appears to be closer to the tail end.

A tactile illusion where tapping separate regions of a person's skin in rapid succession (e.g. the elbow and the forearm) gives the impression of sequential taps "hopping" from one point to the next, even though the intermediate points were never touched.