clo·sure   (klō'zhər)    n.   The act of closing or the state of being closed: closure of an incision. Something that closes or shuts. A bringing to an end; a conclusion: finally brought the project to closure. A feeling of finality or resolution, especially after a traumatic experience. See cloture. The property of being mathematically closed. tr.v.   clo·sured, clo·sur·ing, clo·sures To cloture (a debate). [Middle English, from Old French, from Late Latin clausūra, fortress, lock, from clausus, enclosed; see close. Sense 4, translation of French clôture.]

Closure

Clo"sure\ (?, 135), n. [Of. closure, L. clausura, fr. clauedere to shut. See Close, v. t.]

1. The act of shutting; a closing; as, the closure of a chink.

2. That which closes or shuts; that by which separate parts are fastened or closed.

Without a seal, wafer, or any closure whatever. --Pope.

3. That which incloses or confines; an inclosure.

O thou bloody prison . . . Within the guilty closure of thy walls Richard the Second here was hacked to death. --Shak.

4. A conclusion; an end. [Obs.] --Shak.

5. (Parliamentary Practice) A method of putting an end to debate and securing an immediate vote upon a measure before a legislative body. It is similar in effect to the previous question. It was first introduced into the British House of Commons in 1882. The French word cl[^o]ture was originally applied to this proceeding.

closure 

Main Entry: clo·sure
Pronunciation: 'klO-zh&r
Function: noun
1 a : an act of closing up or condition of being closed up <closureof the eyelids> closure of fontanels and sutures —W. A. D. Anderson> b : a drawing together of edges or parts to form a united integument closure by suture immediately after laceration>
2 : a cap, lid, or stopper for sealing a container (as a serum vial)
3 : the perception of incompletefigures or situations as though complete by ignoring the missing parts or by compensating for them by projection based on past experience

closure
1. In a reduction system, a closure is a data structure that holds an expression and an environment of variable bindings in which that expression is to be evaluated. The variables may be local or global. Closures are used to represent unevaluated expressions when implementing functional programming languages with lazy evaluation. In a real implementation, both expression and environment are represented by pointers.
A suspension is a closure which includes a flag to say whether or not it has been evaluated. The term "thunk" has come to be synonymous with "closure" but originated outside functional programming.
2. In domain theory, given a partially ordered set, D and a subset, X of D, the upward closure of X in D is the union over all x in X of the sets of all d in D such that x <= d. Thus the upward closure of X in D contains the elements of X and any greater element of D. A set is "upward closed" if it is the same as its upward closure, i.e. any d greater than an element is also an element. The downward closure (or "left closure") is similar but with d <= x. A downward closed set is one for which any d less than an element is also an element.
("<=" is written in LaTeX as subseteq and the upward closure of X in D is written \uparrow_\D X).
(1994-12-16)