Thigmonastic

Part of speech: adjective

Definitions

1. Relating to or involving a response to touch or physical contact with a surface or object
2. Characterized by a reaction or behavior triggered by tactile stimulation or pressure from touching
3. Pertaining to responses or movements that are initiated by or dependent upon physical contact or pressure

Etymology: Thigmonastic is an adjective describing a plant movement, which is what makes it an unusual compound: it is built from Greek roots that were assembled in modern scientific English rather than inherited from antiquity. The first element, "thigma", is the Greek word for touch, and the second, "nastos", comes from the verb "nassein", meaning to press down or cram. The result describes a plant that responds to contact, the way a Venus flytrap snaps shut or a sensitive plant folds its leaves when touched. The word is the adjectival form of "thigmonasty", the noun for that touch-triggered response, with the suffix "-ic" added to turn it into a descriptive term. Botanists formed the noun first, and the adjective follows the same pattern as many other scientific terms built from classical parts.