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
Naming of chemical elements planets, dwarf planets, a few asteroids, our star, our planet, and our Moon. Uranium, neptunium, plutonium, cerium, and palladium were named after Uranus, Neptune, Pluto, Ceres, and Pallas respectively, which were at the time of their naming all considered to be planets. (Today, Pluto and Ceres are considered to be dwarf planets, and Pallas is considered to be an asteroid.) The name of the element selenium came from the Greek word for the Moon (Σελήνη, "Selene"). The name helium comes from the Greek word for the Sun (Ἢλιος, "Helios"). This is because the first evidence for helium was in distinctive,