Studio
A flat piece of wood is called a board.
plumage
A flat cut on a precious stone is called a "table cut". It is a cut where the top of the stone is polished flat with large facets.
Flat open land is called a plain. A plain is a flat area with few trees. They can occur as lowlands and at the bottom of valleys, but can also be on plateaus or uplands at high elevations.
A flat spoon is called a spatula. It is typically used for lifting, flipping, or spreading food while cooking.
Liam Payne
One flat surface is a table. Many flat surfaces are facets.
A by-room is an adjoining room or apartment to a building.
It is called a "natural" sign, and it cancels out/naturalizes a sharp or a flat.
Hemisphere
Roomed is the past tense of room.
One word I can think of is bedsit. Another is studio.Both are small-roomed residences.
The flat surfaces of all polyhedra are called faces and a rectangular prism is simply one kind of polyhedron.
A guitar with a flat body instead of a curved one is called a "solid-body guitar."
A line segment
A 3 bed roomed house is a house with three rooms for sleeping in, in other words it will have (at least) a kitchen, bathroom, toilet, sitting room and three bedrooms.
pueblos were used as multi-roomed housing for the anasazi