(of a set) The set of points in the closure of a set S, not belonging to the interior of that set.
An edge or line marking an edge of the playing field.
The bounds, confines, or limits between immaterial things (such as oneβs comfort zone, privacy, or professional sphere and the realm beyond).
The dividing line or location between two areas.
An event whereby the ball is struck and either touches or passes over a boundary (with or without bouncing), usually resulting in an award of 4 (four) or 6 (six) runs respectively for the batting team.
A non-empty lower set (of a partially ordered set) which is closed under binary suprema (a.k.a. joins).
A subsemigroup with the property that if any semigroup element outside of it is added to any one of its members, the result must lie outside of it.
A subring closed under multiplication by its containing ring.
A collection of sets, considered small or negligible, such that every subset of each member and the union of any two members are also members of the collection.
A perfect standard of beauty, intellect etc., or a standard of excellence to aim at.
A Lie subalgebra (subspace that is closed under the Lie bracket) π of a given Lie algebra π such that the Lie bracket [π,π] is a subset of π.
Not actually present, but considered as present when limits at infinity are included.
Optimal; being the best possibility.
Existing only in the mind; conceptual, imaginary.
Pertaining to ideas, or to a given idea.
Perfect, flawless, having no defects.
Teaching or relating to the doctrine of idealism.