LED Tubes and Retrofit Kits
An LED lamp is simply a light-emitting diode that is assembled into a lamp (lamp length can be from 12" to 48") that produces white light when power is applied. An LED retrofit kit is the use of light-emitting diodes on a chip form with additional hardware like brackets, sockets, screws, and fasteners. Both LED Lamps and LED Retrofit Kits require a fixture to provide housing.
LED Luminaires are light emitting diodes housed in a fixture assembly presented as one whole product. This one product includes all parts to distribute the light, protect the LEDs and connect to a power supply. The power supply is the only additional piece required to produce light visible from the LED luminaire.
An LED Fixture is the physical housing that protects and positions the LED lamp/retrofit kit into place.