The very common “can light” can be found everywhere, from homes to commercial buildings. Yet they go by numerous names. Can Lights are also known as High-Hats, and in Canada the term Pot Light is common. These days Can Lights are often simply referred to as Recessed Downlights (there are, though, other types of luminaires within the Recessed Downlight category).
Can Lights have three primary features: the housing (can) is recessed into the ceiling; the decorative trim is flush with the ceiling; and the lamp/LED source is recessed to reduce glare. Besides giving ceilings a clean look, the recessed nature of the light source of a Can Light allows the luminaire to throw out a considerable amount of light with low glare.
Can Lights come with integral recessed LED, or with medium based (E26) sockets. The recessed housing is comprised of the “can” with mounting brackets, or a box with the can inside. The housing is installed prior to the finished ceiling (from which the housing gets the nickname “rough-in”). There are also Retrofit and Remodel Downlights which have different housings to accommodate installation in finished ceilings. (As a side note, beware of new retrofit products that have a lens flush with the ceiling, as this will significantly increase glare. Always try a sample first to see if this look is acceptable. In general, using a remodel type luminaire if possible, and not a retrofit, is almost always the better option.)