Lamp, Light Bulb, Luminaire, Light Fixture – What is the difference?

What exactly do the terms lamp, light bulb, luminaire and light fixture mean? You should know about the correct definition of all these words. This is especially important, if you are looking online about products for your home lighting. Here you will find out the difference between these terms.

Complicated terms for simple lighting?

When you are surfing online in a lighting shop you are often faced with the following terms:

  • lamp
  • light bulb
  • light source
  • illuminant
  • luminaire
  • light fixture

Many times these words were used in an ambiguous way. In the following paragraphs we will explain the exact definition of these terms.

Lamp and light

The words lamp and light bring in the most confusion. If you go to the DIY store and simply ask for a lamp, the seller won’t probably know what you want. This is only possible if you combine other terms with the word lamp. Whoever asks for a desk lamp can be helped. And who looks for a floor lamp for its cabinet, might also get help.

The word lamp is often used in everyday language as a synonym for all the other defined lighting terms on this page. With an LED lamp a bulb could be meant but the term could also refer to a light fixture including the bulb. As you can see it is not always clear. To be more precise you should use the following terms.

Luminaire and light fixture

The luminaire or so called light fixture is the entire construction around the light source. It consists of several components such as mounting, lampholder, reflector, shade or glass cover. Inside the luminaire is the actual light source, which is called the illuminant. There are many different types of luminaires for different applications. These include ceiling luminaires, wall luminaires and so on.

In everyday language, however, the term light fixture is used more often instead of the word luminaire. Instead of a desk luminaire, we prefer to speak of a desk lamp. The terms luminaire, light fixture and lamp are therefore often used as synonyms. However, the term desk lamp is technically correct. In this case the word lamp describes the entire construction of the components mentioned above.

Illuminants, light bulbs and light sources

Until a few years ago, most luminaires were equipped with normal incandescent lamps. Since the spread of new light sources, the term illuminant is more established. Due to the many new lighting techniques, the term lamp is often too general. In contrast, the word illuminant refers very precisely to the actual light source. But in consumer field the term light bulb is used most frequently.

Usually the term is used in combination with lighting technology such as LED light bulb or halogen light bulb. In combination with the required socket, it is even easier to find the desired illuminant such as an E26 LED bulb. On the other hand, if you are only looking for an LED lamp, you will find both LED luminaires and LED bulbs on offer.

Do you know the difference now?

If you want to be very precise and technically correct, you should only use the terms luminaire, light fixture and illuminant for the light source. These are very precise and there is very little confusion. As described above, the word lamp is very general. Depending on the context, this can mean both the fixture or the illuminant.

Especially if you are looking online for a new ceiling light, the difference between a lamp and a luminaire becomes clear. The search term “luminaire” can often be used to find the right results. If you search with the word lamp, it depends very much on the attached terms.

Strictly speaking, an LED lamp can be either a luminaire or a light source. An LED desk lamp clearly means a luminaire and an LED lamp E26 unmistakably means an LED bulb with an E26 socket.