Learn Portuguese (Portugal): Acendo o candeeiro à noite.

While ligar means "to turn on" for most electronics, acender originally means "to light" (like a fire). It is the most natural and traditional choice for turning on lights and lamps like o candeeiro. You will hear both used in everyday speech, but acender is very specific to sources of illumination.

I thought "lamp" was a lâmpada. Why use o candeeiro?

This is a common mix-up! O candeeiro is the actual lamp fixture (the base, the stem, and the shade). A lâmpada is just the lightbulb inside it. You turn on o candeeiro, but you change a lâmpada when it burns out.

Why does the sentence use à noite instead of de noite?

Both translate to "at night" and are often interchangeable. However, à noite (which merges the preposition a with the feminine "the" word a) is typically used for routines or specific events happening in the evening, like turning on a light. De noite tends to describe the general state or condition of nighttime.