Trichloro

Part of speech: adjective

Definitions

1. Used in chemistry as a prefix indicating that a compound contains three chlorine atoms substituted into its molecular structure
2. A chemical combining form signifying that three chlorine atoms have replaced hydrogen or other atoms in a compound
3. Denotes a molecule in which three chlorine atoms are attached, as in names of organic compounds such as trichloroethylene

Etymology: "Trichloro" is a chemistry prefix meaning "with three chlorine atoms," and it is built from two Greek-derived pieces. The first, "tri-", is the familiar number-prefix from Greek "treis" (three). The second, "chloro-", comes from Ancient Greek "khlōrós," which meant "pale green" or "greenish yellow," the colour of fresh young shoots and leaves. That same root gives English "chlorophyll," the green pigment of plants. The colour sense explains the name of the element itself. Chlorine, a greenish-yellow gas, was named for its hue, and chemists then used "chloro-" as a combining form whenever a compound contained chlorine. Adding "tri-" to it gives a precise instruction: the molecule carries three chlorine atoms, as in trichloromethane, the compound once widely known as chloroform.