sider(o)-

Iron.

Greek sidēros, iron.

A siderophore is a molecule in micro-organisms which binds and transports iron; a sideroblast is an iron-rich red blood cell in the bone marrow; a siderophile is something that has an affinity for iron; sideropenia is iron deficiency in the body; siderosis is a deposition of iron in the lungs, an occupational disease of arc welders; siderite is either an ore of iron, or a meteorite consisting mostly of nickel and iron.

A few terms contain instead Latin sidus, sider‑, a star: a siderostat is an instrument used for keeping the image of a celestial object in a fixed position; a siderograph is a chart of planetary positions used in financial astrology, and sidereal is the adjective referring to the stars, as opposed to the sun or planets.