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A recessed light or downlight is a ceiling light fixture that is installed into a hollow opening in the ceiling. When installed it appears to have light shining from a hole in the ceiling, concentrating the light in a downward direction. There are two parts to recessed lights, the trim and housing. The trim is the visible portion of the light. It is the insert that you see when you look up and also includes the thin lining around the edge of the light. The housing is the fixture itself that is installed inside the ceiling and contains the light socket. Also known as canister lights.

Uplight is another kind of light fixture. It is similar to the downlight and it is also installed into a hollow. The only difference is that the hollow is not opening in the ceiling. Instead, it is installing on the floor or just fixed on the pole.

一般裝修行業的人會稱之謂「筒燈」，downlight 和 uplight 的分別在於一種安裝在天花裡、一種放致在地上。

參考以下兩間公司的圖片就可以明白。
http://www.sft.com.cn/english/products_5.asp
http://www.lampsplus.com/Products/s_uplight/