Separation may refer to a several different subjects:

• In chemistry, separation refers to separation processes.
• In Gemology, separation refers to the identification process criteria of species of minerals, of treatments made to these minerals, and of natural or synthetic origin.
• In landscaping and architecture, a wall or ditch that divides a space is sometimes called a separation.
• In interpersonal relationships, separation usually refers a married couple ceasing to live together, but without getting a divorce.
• Legal separation is a legal status where married couples may disentangle their finances without divorce.
• In audio mastering, a separation is a single track containing one or more major song elements. When all separations are recombined, the 2-track mix is recreated (see Separation mastering).
• In descriptive set theory, the separation property for a pointclass allows separating two disjoint sets in the pointclass by another set in the same pointclass.
• In topology, the separation axioms are properties that topological spaces may have which tell roughly how many open sets can contain two points.
• In fluid mechanics, separation refers to a phenomenon where a fluid flows along a surface for some distance, but due to adverse pressure gradients, flows away from the surface rather than following it further. In other words, it is what happens when the Coanda Effect can no longer make a fluid "stick" to a surface. Examples are a wing stall, and the separation along the sides of bluff bodies which lead to wake formation and pressure drag.
• Separation (EP), an extended-play record by Halou.
• In air traffic control, controllers apply separation rules to minimise the risk of collision between aircraft in flight.