• A compound is an area of land that is surrounded by fences, walls, or barbed wire and is used for a particular purpose, especially an area containing buildings and where the entry and exit of people is controlled.
• In chemistry, a compound (chemical compound) is a chemical combination of two or more elements. See list of compounds.
• In linguistic morphology, a compound is a word that consists of more than one radical element, for example summertime. See also English compound. This is not to be confused with a complex phrase.
• In botany, compound is a quality of leaves. Leaves that are compound are in an array of small, symmetrically-arranged leaflets on each stem. In contrast, a plant with simple leaves has one leaf per stem.
• In economics, Compound Annual Growth Rate (CAGR) is the average annual growth rate of a value over a given number of years.
• In music, a compound is an attribute to an interval. An interval that is compound is an interval which exceeds or is wider than one octave. In contrast, a simple interval lies within one octave.
• In steam locomotive engineering, a compound locomotive has steam that is passed that has already passed through one cylinder is then passed through another; i.e. the cylinders are in "series" as opposed to the normal arrangement of a simple locomotive in which the cylinders are in parallel.