Evagination

Part of speech: noun

Definitions

1. The protrusion or outpouching of a structure, especially tissue or membrane, from its normal position or surface
2. The process or result of an internal structure extending outward through or beyond its surrounding boundary
3. A biological condition in which tissue or an organ pushes outward from its normal contained position

Etymology: "Evagination" is a technical term from biology and medicine, and its history is plain: it was borrowed from Latin "ēvāginātiō", a noun meaning a drawing out of a sheath. The Latin word is built from "ē", "out of", and "vāgīna", "sheath", the same root that gave English "vagina", which in Latin meant a scabbard or sheath for a sword. The English form follows the pattern of "evaginate", a verb meaning to turn or push a sheath-like structure outward, combined with the common noun ending "-ion", which turns a verb into the name of the action or its result. The word thus describes a process in which tissue is pushed outward from within, like a glove turned inside out or a sword drawn from its scabbard. Its meaning is literal and concrete, which is why it sits comfortably in anatomical and developmental descriptions rather than in everyday speech.

Synonyms: protrusion, extension