A scheme for the ordering of things such as stellar objects, minerals, forms of life, or personality types according to characteristics that are discernible and testable by scientific methods.

(rail transport, US) a railroad yard where incoming freight trains are sorted into various sidings.

plural of classification yard

A scale used to classify the depth of the olfactory fossa.

plural of classification scheme

A standard North Atlantic Treaty Organization system in which a route and aircraft, bridge, or raft is assigned class number(s) representing the load it can carry; vehicles are also assigned class number(s) indicating the maximum class of route, bridge, or raft they are authorized to use.

(library studies) A proprietary library classification system that allows new books to be added to a library in their appropriate location based on subject.