Ruled

Ruled is the past tense and past participle of the verb rule. It describes governance or authority over a person, place, or domain, as in a country that is ruled by a monarchy or by an elected government. It can also refer to decisions, laws, or policies that govern behavior, such as rules that rule out certain actions or actions that are ruled by a regulatory framework.

Ruled paper refers to sheets printed with horizontal lines to guide handwriting. The lines help keep text evenly aligned and are often accompanied by margins. Common variants include wide-ruled and college-ruled, which differ in line spacing. Ruled paper is widely used in schools, offices, and personal note-taking, and it may come in different sizes and formats.

In geometry, a ruled surface is a surface that can be generated by moving a straight line through space. Equivalently, through every point on the surface there exists at least one straight line contained entirely in the surface. Classic examples include cylinders and cones; many other curved surfaces, such as the hyperbolic paraboloid, are also ruled. Non-ruled surfaces, like spheres, do not contain a straight line that lies entirely on the surface.

Usage notes include the distinction between governance and physical descriptions: in political contexts, ruled emphasizes sovereignty or control, while in writing and geometry it refers to the presence of lines or a constructive method. The term is common across disciplines and everyday language.