The term IT MAY BE NATURAL OR NOBLE can be solved by the three letter word GAS. GAS is a general term used to describe a wide variety of substances in a gaseous state at normal atmospheric pressure. It can refer to both natural gases, such as methane, and noble gases, such as helium. Natural gases are found in underground reservoirs and are composed of hydrocarbons, while noble gases are found in the atmosphere and are composed of single atoms.