Triterpenes

Part of speech: noun

Definitions

1. Organic compounds built from six isoprene units, forming a large family of natural molecules found in plants, fungi and animals
2. A large group of naturally occurring chemical compounds composed of six isoprene units, including many plant resins, steroids and pigments
3. Natural lipid-like molecules made up of six isoprene subunits, widely distributed in living organisms and often used in medicine

Etymology: Triterpenes are a plural form, so the story belongs to the singular "triterpene," which is simply a chemical name assembled from two parts. The first part, "tri-," comes from Latin and Greek, where it means "three," and chemists have long used it to signal a count of three. The second part, "terpene," is itself a chemical coinage built from "terpentin," the German word for turpentine, the resin-derived liquid that the class of compounds was first associated with. Joined together, "triterpene" names a compound built from larger units than the simpler terpenes. The "-ene" ending is the chemist's standard marker for an unsaturated hydrocarbon, which is why the name carries that form. Because the term is a technical coinage rather than an old word, its history is recent and traceable to the chemistry of the nineteenth and twentieth centuries.