A torchiere floor lamp or "torch lamp", is a tall standing lamp which stands on the floor. The shade on the lamp will direct almost all of its light upwards towards the ceiling. This light will then bounce and diffuse off the ceiling, illuminating the general area with a softer background light.
When switched on, a torchiere floor lamps will light up at least most of the room. You can locate them in a corner or next to a desk or chair and they will light up the surrounding area well. But if you want to light the whole room, you might want to consider placing a lamp near either end of the room.
A torchiere floor lamp tends to have quite strong brightness compared to other lamps. Typically you'll find an equivalent or at least 250-300 watts incandescent, or more. Usually a torchiere will feature either a full-spectrum or led bulb system, and may feature multiple light bulbs. Tall torchiere lamps are designed to be quite bright so as to provide a strong yet mostly local illumination.
A torchiere-style floor lamp will add quite a lot of brightness to a room, such as in evening time or under darker weather. This brightness will usually be sufficient for most activities. But for a larger room you might want to consider two of them. They're usually ideal to be placed in a corner or side of a room, or near to a desk or seating area. The light from a torchiere will cover a fairly large area but the other side of the room will be darker. Torchiere lamps are typically quite bright lamps.
A torchier will usually have a switch either near or just below the lamp head, or somewhere on the lamp pole, or possible a foot operated switch. A foot switch is easily operated by simply tapping the switch with your foot. It may also use an in-line dimmer switch. A switch on the pole is easy to reach at arm's length to switch the lamp on.
Modern torchiere lamps may include led torchiere lamps, possibly with a touch switch. They might also be operated by a remote control which may allow you to adjust not only the timing of the lamp being on, but also the color of the light and its brightness. Many modern floor lamps look sleek and contemporary and may also allow you to tilt and angle the lamp head to somewhat aim the light.
A subset of torch-style lamps is a tiffany torchiere lamp. The tiffany glass shade surrounds the light and is brightly colored when lit. Some of the light will pass through the stained glass pieces, illuminating the room with colored light. Some of the light will still shine directly upwards but light passing through the shade will provide colorful decoration and appeal.