In technical theater

Stagecraft

Stagecraft is a generic term referring to the technical aspects of theatrical, film, and video production. It includes, but is not limited to, constructing and rigging scenery, hanging and focusing of lighting, design and procurement of costumes, makeup, procurement of props, stage management, and...

, spot rigging is the practice of using a fly system

Fly system

A fly system, flying system or theatrical rigging system, is a system of lines , blocks , counterweights and related devices within a theatre that enable a stage crew to quickly, quietly and safely fly components such as curtains, lights, scenery, stage effects and, sometimes, people...

 to fly something specific for a show which does not use the venue's standard rigging. For example, flying scenery

Theatrical scenery

Theatrical scenery is that which is used as a setting for a theatrical production. Scenery may be just about anything, from a single chair to an elaborately re-created street, no matter how large or how small, whether or not the item was custom-made or is, in fact, the genuine item, appropriated...

 on an ordinary batten

Batten

A batten is a thin strip of solid material, typically made from wood, plastic or metal. Battens are used in building construction and various other fields as both structural and purely cosmetic elements...

 would not qualify as spot rigging; flying a chandelier on a dedicated line would be. Likewise, if a wall were being flown in on a batten which was installed at an angle neither parallel nor perpendicular to the proscenium

Proscenium

A proscenium theatre is a theatre space whose primary feature is a large frame or arch , which is located at or near the front of the stage...

line, it would qualify as spot rigging, because custom setting of lift lines would be required.