Trivial name for example, hydrogen ("water-producing"), oxygen ("acid-producing"), nitrogen ("soda-producing"), bromine ("stink"), and argon ("no reaction") were based on Greek roots, while the names of iodine and chlorine were derived from the Greek words for their characteristic colors. Indium, rubidium, and thallium were similarly named for the colors of particular lines in their emission spectra. Iridium, which forms compounds of many different colors, takes its name from "iris", the Latin for "rainbow". The noble gases have all been named for their origin or properties. Helium comes from the Greek "helios", meaning "sun" because it was first detected as a line in the
Shades of green a color name in English was in 1805. "Avocado" is a color that is a representation of the color of the outer surface of an avocado. The color avocado is a dark yellow-green color. Avocado was a common color for metal surfaces (including automobiles and household appliances), as well as the color harvest gold, during the whole decade of the 1970s. They were both also popular colors for shag carpets. Both colors went out of style by the early 1980s. "Dark green" is a dark shade of green. A different shade of green has been designated as "dark green (X11)"