Parts of a Light Fixture – Labeled Ceiling Light Diagram

All 11 parts on the diagram

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The fixture 6

Shade It spreads and softens the light. On a ceiling fixture it is often a bowl or dome of frosted glass.
Bulb The source of the light. Lighting engineers call it the lamp. Everyone else calls it the light bulb.
Socket The holder a bulb fits into. It lets a bulb be changed easily.
Canopy The cover at the ceiling. It hides the outlet box and the wire connections inside it.
Fixture body The main part of the fixture, which carries the sockets. Every light fixture has a body and at least one light source.
Finial A knob screwed onto the end of the center rod. It holds the glass on; unscrew it to take the glass off.

At the ceiling 5

Outlet box A metal box in the ceiling where the house wiring ends. The fixture is mounted to it. Also called a junction box or ceiling box.
Mounting strap (crossbar) A flat metal bar screwed across the outlet box. The rest of the fixture hangs from it. Some makers call it a crossbar.
Nipple A short threaded tube screwed into the middle of the strap. Other parts of the fixture screw onto it.
Ground screw A screw on the strap. The fixture's ground wire is wrapped round it. It is usually green.
Wire connectors Small caps twisted over each pair of joined wire ends. Also called wire nuts.

How this list was compiled: Part names checked on 2026-09-30; a name is kept only when two independent sources use it. (1) Wikipedia, Light fixture, text only, https://en.wikipedia.org/wiki/Light_fixture (fixture body, light sources in sockets, shade, the knob at the center of a ceiling dome, lamp and light bulb). (2) One maker's installation guides for a flush-mount fixture and a chandelier, https://archive.org/details/manualzilla-id-6938389 and https://archive.org/details/manualzilla-id-6942799, counted as one source (canopy, socket, bulb, nipple, shade, finial, mounting strap, outlet box, wire connectors, ground screw). (3) A second maker's installation sheets, https://archive.org/details/manualsbase-id-183183 and https://archive.org/details/manualsbase-id-182872, counted as one source (canopy, outlet box and junction box, crossbar and mounting strap, nipple, wire connectors and wire nuts, green ground screw, fixture body, glass, finial). (4) Rachel Martens, The How-to Book of Repairing, Rewiring, and Restoring Lamps and Lighting Fixtures (1979), read through the Internet Archive's full-text search, https://archive.org/details/howtobookofrepai00mart (canopy, outlet box, crossbar, nipple, wire nut, socket, finial). Makers are named here only; the page names none. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's product is copied and nothing is traced. Licence: own work

How it works

These are the parts of a ceiling light fixture: the ones you see from the room, and the ones hidden at the ceiling that hold it up and connect it.

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What you see from the room

The canopy sits against the ceiling. Below it the fixture body carries the sockets, and a bulb goes in each. The glass shade surrounds the bulbs, and the finial under it holds the glass on.

What the canopy hides

Behind the canopy is an outlet box set in the ceiling. A mounting strap, also called a crossbar, is screwed across the box, and a threaded nipple hangs from its middle. Wire connectors join the fixture's wires to the house wires, and the ground screw sits on the strap.

Wire connectors and wire nuts are two names for the same small caps.
Outlet box, junction box and ceiling box all name the box in the ceiling.

Questions and answers

What are the parts of a light fixture called?

From the ceiling down: the canopy, the fixture body, the sockets, the bulbs, the shade and the finial. Hidden behind the canopy are the outlet box, the mounting strap, the nipple, the ground screw and the wire connectors.

What is the part of a light fixture that attaches to the ceiling called?

The canopy is the cover you see against the ceiling. Behind it, a mounting strap, or crossbar, is screwed across the outlet box, and the fixture hangs from that.

What is the knob on the bottom of a ceiling light called?

A finial. It screws onto the end of the rod that runs down the middle of the fixture and holds the glass shade on. Unscrewing it releases the glass.

What is the glass part of a light fixture called?

The shade. It spreads and softens the light, and on a ceiling fixture it is often a bowl or dome of frosted glass.