Chiasm

Part of speech: noun

Pronunciation: /ˈkaɪ.æzəm/

Definitions

1. This term describes a symmetrical configuration, often exhibiting a mirrored or inverted relationship between paired elements
2. A specific arrangement in which two elements intersect or cross, often reflecting a mirrored or inverted relationship between their components
3. This refers to a structural pattern where intersecting elements create a symmetrical relationship, frequently revealing inversion or mirroring

Etymology: The Greek letter chi, written as an X, is the key to this word. The ancient Greek verb "khiazein" meant "to mark with a chi," and from it came "khiasmos," a crossing or diagonal arrangement, named for the shape of that letter. The Greeks also used "khiasma" for things that cross, such as the X-shaped junction of the optic nerves, and Latin took the word over as "chiasma." English has two senses that grew from these roots. In anatomy, a chiasm is the point where nerves or structures cross over one another, most famously the optic chiasm behind the eyes. In rhetoric, the sense is a reversal of word order across a pair of phrases, as in "Ask not what your country can do for you; ask what you can do for your country." That rhetorical sense is also called chiasmus, a form borrowed from the same Greek source, so the two terms were built from the same letter-shaped idea but have settled into different corners of English.