Use this tag for questions about the placement of the object origin, or about the origin in the various coordinate systems such as local and world.
Blender uses origin to refer to the Object Origin which the manual describes thus:
Each object has an origin point. The location of this point determines where the object is located in 3D space. When an object is selected, a small circle appears, denoting the origin point. The location of the origin point is important when translating, rotating or scaling an object.
Origin can also refer to the point in a coordinate system located at (0, 0, 0) in that coordinate system. In the 3DViewport, the default origin is called the World origin.