Eicosane

Part of speech: noun

Definitions

1. A waxy hydrocarbon compound made of twenty carbon atoms linked in a straight chain with hydrogen atoms attached
2. An organic alkane molecule containing twenty carbon atoms, found in petroleum and used in chemical research
3. A saturated hydrocarbon with the formula C20H42, belonging to the family of straight-chain alkanes

Etymology: Eicosane is a systematic chemical name, built to a plan rather than inherited from everyday speech. Its first part comes from "eicos", the Greek word for "twenty", and the second part, "-ane", is the suffix IUPAC chemists use for saturated hydrocarbons in the alkane series. Put together, the name tells you the molecule has twenty carbon atoms linked in a chain, with every other bond filled by hydrogen. The pattern is the same one behind names like methane (one carbon) and octane (eight), so a chemist who knows the Greek numeral and the suffix can work out the structure from the name alone. The word is therefore less a story of drift in meaning than a small piece of logic written into vocabulary: each syllable records a fact about the molecule.