Concentration can refer to: Science, engineering, and technology Concentration, in chemistry, the measure of how much of a given substance there is mixed with another substance Mass concentration (astronomy), a region of a planet or moon's crust that is denser than average Number density in physics, chemistry, and astronomy Entertainment Concentration (card game), the card game Concentration (game show), American television game show Concentration (album), an album by Machines of Loving Grace Concentration 20, an album by Namie Amuro Psychology Attentional control, the cognitive process of controlling the focus of attention Religion Samadhi (Buddhism), mental concentration in Buddhism Economics Market concentration, in economics, the number and production share of firms in a market (or industry) Concentration ratio, in economics, a measure of market concentration. Other uses Concentration camp, a detention center created for specific groups of people, usually during wartime A term used at Brown University, Colgate University, Columbia University, Harvard College, and Saint Olaf College to refer to a type of academic major Force concentration, and concentrate, in military tactics, the practice of concentrating military units See also Concentrate (disambiguation)