Which term refers to any unit of light equipment?

The correct term that refers to any unit of light equipment is "luminaire." A luminaire encompasses an entire lighting unit, including the lamp (light source) and all the components necessary to distribute light, control Diffusion, and support the lamp. This term is widely used in both theatrical and architectural contexts to indicate a complete lighting fixture that serves a defined purpose in illuminating a space.

While "lantern" may be used informally to describe various lighting devices, it does not encompass all units of light equipment as broadly as "luminaire." Lanterns typically refer to specific types of lights or fixtures meant for portable use, often with a traditional or decorative design.

"Limelight" refers to a specific type of theatrical lighting from the past that involved producing light through igniting quicklime; it's not a general term for lighting equipment.

Parcan is a specific type of lighting fixture that is commonly used in theatre and music performances, but it doesn't represent the full range of light equipment units. The term "luminaire" correctly denotes any unit of light equipment in a comprehensive way.