—n. 1. Archit. a. a vault, having a circular plan and usually in the form of a portion of a sphere, so constructed as to exert an equal thrust in all directions.
b. a domical roof or ceiling.
c. a polygonal vault, ceiling, or roof.
2. any covering thought to resemble the hemispherical vault of a building or room: the great dome of the sky. 3. anything shaped like a hemisphere or inverted bowl.
4. (in a dam) a semidome having its convex surface toward the impounded water.
5. Crystall.a form having planes that intersect the vertical axis and are parallel to one of the lateral axes.
7. Also called vistadome.Railroads.a raised, glass-enclosed section of the roof of a passenger car, placed over an elevated section of seats to afford passengers a full view of scenery.
8. Horol.an inner cover for the works of a watch, which snaps into the rim of the case.
9. a mountain peak having a rounded summit.
10. Slang.a person's head: I wish I could get the idea into that thick dome of yours.
—v.t. 1. to cover with or as if with a dome.
2. to shape like a dome.