Street Light Technical Information
Willis Lamm

A Visual Glossary of Terms

This list of terms is provided so that those persons collecting and/or restoring vintage street lights have available to them the proper terms for the various components associated with different street light designs. Proper terminology can help us describe our lamps as well as help us locate needed parts used in restorations.

The terms used in this glossary have been taken from original technical drawings and descriptions.


A thru H

Slang term for a post mounted globe that resembles an acorn.

Visible light from current passing through air or gas.

Arc Light
An early street light where light was produced by an arc maintained between two carbon rods.

A magnetic coil device that drops high tension series circuit voltage to appropriate lamp voltage in early lighting systems

Auxiliary Reflector
A secondary internal reflector designed to split the direction of light, generally used in fluorescent luminaires.

A magnetic coil device that increases or reduces current passing through a fluorescent or vapor discharge lamp.

Ballast Box
A compartment at the base of older mercury vapor street light standards in which ballasts were located.

Bayonet - (Bayonet Contacts)
Connection contacts on a removable series circuit socket.

Binding Post
A heavy terminal in which a large conductor or wire attaches.

Bishop's Crook
A bracket arm that has a sweeping upward, then downward bend at the end resembling a bishop's crook.

The main portion of an overhead luminaire that contains the lamp socket, also called a head, generally applied to all-aluminum luminaire heads.

A pendant glass refractor, such as a gumball.

Bracket Arm
An arm that extends from a mast or utility pole that holds a street light, also called a mast arm.

The metal cap or crown that threads onto a bracket arm and holds the street light body.

Alternative term for Canopy.

Name for the electrodes used in carbon arc lamps.

Synonym for "body" in post lamp luminaires.

(1) A tightening collar on a slip fitter. (2) An adjustable ring that attaches a scroll to a bracket arm.

Common name for a mercury vapor luminaire that is ovate in shape and roughly resembles a clam shell.

A common name for a mercury vapor or sodium vapor luminaire in which the ballast and electronic components are contained in a body that is shaped roughly like a the head of a cobra.

A metal band, usually with a screw or bolt with which to tighten it, that attaches a round refractor to a round reflector.

A metal or concrete pole to which a bracket arm is attached, also referred to as a mast.

A wire supplying power to a street light.

Receptacle contacts for a socket bayonet.

Closed Circuit
A circuit that is complete and operating.

Closed Loop
A high tension series lighting circuit wherein both leads run on the same utility poles or in the same underground conduit.

Alternative term for Canopy.

(1) A fuse in a high tension circuit. (2) A film coated device for automatically shunting a burned out lamp in a series circuit.

A condition when a mercury vapor or sodium vapor lamp continuously extinguishes and relights.

A hinged bottom plate on some cobrahead luminaires that holds the reflector-refractor elements and ballast components, allowing all to swing down.

Decorative Fitting
A angled threaded fitting or slip fitter, usually 90 degrees, that has a decorative design.

Deep Bowl
A long pendant refractor often called a "teardrop."

Internally mounted reflector designed to deflect light away from an undesirable lateral direction.

Defuser (Defusing Refractor)
A glass refractor that has a ripple finish to diffuse light.

A nickname for a film disc cutout as they are about the size of a dime.

The inner closed tube of a gaseous arc lamp (such as a mercury vapor or sodium vapor lamp) in which the gas is ionized.

(1) A rod, usually carbon based, used to strike an arc in arc lamps. (2) A conductor where electrical energy enters a gas-filled lamp.

External Wiring
Wiring that exits directly from the luminaire body and runs to the source of power, traveling outside of the bracket arm.

Film Cutout
A small film coated insulating device that breaks down when high current is applied and thus conducts electricity. Film cutouts are typically used in series lighting circuits to close the circuit when a lamp burns out in order to keep the remaining lamps lit.

A pointed ornament most often found atop a post mounted acorn lamp.

A threaded connection between two components, usually between a luminaire canopy and the bracket arm.

Fluorescent - Fluorescent Lamp
A lamp in which illumination is provided by fluorescent phosphors that are excited by ultraviolet energy.

A sphere of glass surrounding a light source, most commonly on post type luminaires. Other glass refractors such as acorns and gumballs are sometimes referred to as globes.

Common term for a pendant or bracket arm mounted luminaire in which the reflector and refractor combined comprise a shape roughly like a ball.

(1) The ceramic portion of a non-metallic luminaire. (2) A term used for the body of an all-aluminum pendant or side mount luminaire. Head Collar
A clamp type device that secures a ceramic head to a bracket arm slip fitter.

HID - High Intensity Discharge
A term that refers to gaseous arc lamps such as mercury mapor, sodium vapor or metal-halide.

A device for swinging open a refractor or lower luminaire housing.

(1) A term sometimes used to describe the body of a NEMA type pendant luminaire. (2) Synonym for a lamp's external reflector.

Continue to
I thru Z




Ceramic Bodies

Metallic Bodies

Continue to Additional Illustrations

Please note: This glossary is a work in progress. If you notice an error or are aware of something that is missing, please feel free to Email me.


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