Anachronous

An anachronism (from the Greek ἀνά ana, "against" and χρόνος khronos, "time") is a chronological inconsistency in some arrangement, especially a juxtaposition of persons, events, objects, or customs from different periods of time. The most common type of anachronism is an object misplaced in time, but it may be a verbal expression, a technology, a philosophical idea, a musical style, a material, a plant or animal, a custom or anything else associated with a particular period in time so that it is incorrect to place it outside its proper temporal domain.

An anachronism may be either intentional or unintentional. Intentional anachronisms may be introduced into a literary or artistic work to help a contemporary audience engage more readily with a historical period. Anachronism can also be used for purposes of rhetoric, comedy, or shock. Unintentional anachronisms may occur when a writer, artist, or performer is unaware of differences in technology, language, customs, attitudes, or fashions between different historical eras.

A parachronism (from the Greek παρά, "on the side", and χρόνος, "time") is anything that appears in a time period in which it is not normally found (though not sufficiently out of place as to be impossible).

This may be an object, an idiomatic expression, a technology, a philosophical idea, a musical style, a material, a custom, or anything else sufficiently closely bound to a particular time period as to seem strange when encountered in a later era. They may be objects or ideas which were once common, but are now considered rare or inappropriate. They can take the form of obsolete technology or outdated fashion.

Examples of parachronisms could include a suburban housewife in the United States around 1960 using a washboard for laundry (well after washing machines had become the norm); or a teenager from that time period being an avid fan of ragtime music. Often, a parachronism is identified when a work based on a particular era's state of knowledge is read within the context of a later era—with a different state of knowledge. Many scientific works that rely on theories that have later been discredited have become anachronistic with the removal of those underpinnings, and works of speculative fiction often find their speculations outstripped by real-world technological developments or scientific discoveries.

A prochronism (from the Greek πρό, "before", and χρόνος, "time") is an impossible anachronism which occurs when an object or idea has not yet been invented when the situation takes place, and therefore could not have possibly existed at the time (e.g. The Last Supper by Leonardo da Vinci at the top of this page). A prochronism may be an object not yet developed, a verbal expression that had not yet been coined, a philosophy not yet formulated, a breed of animal not yet evolved (or perhaps engineered), or use of a technology that had not yet been created.

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