Triterpene

Part of speech: noun

Definitions

1. Any of a large class of organic compounds built from six isoprene units, found in plants, fungi and animals and including steroids and many natural resins
2. A naturally occurring organic molecule composed of six isoprene units, forming a broad group that includes sterols, certain resins and various plant pigments
3. A terpene compound made up of six isoprene units, a family of chemicals common in plant resins, fungal metabolites and animal steroids

Etymology: Triterpene is a chemical term built from two parts. "Terpene" itself comes from "terpentin," the German word for turpentine, the resinous liquid distilled from pine trees, since the first compounds of this family were obtained from that source. The prefix "tri-" comes from Greek and Latin and means "three," so a triterpene is a terpene made up of three of the basic five-carbon units that link together to build these molecules. Here the count is doubled by the terpene's own structure, giving thirty carbon atoms in the typical skeleton. The "tri-" in this word is the numerical prefix found in many chemical names, from "triangle" to "trimester." Chemists added it to "terpene" to mark the number of units, a sense the word carries without any shift in meaning. The result is a precise label rather than a word with a dramatic history, and its parts have stayed close to their original senses.