Closure

[kloh-zher] /ˈkloʊ ʒər/

noun
1.
the act of closing; the state of being closed.
2.
a bringing to an end; conclusion.
3.
something that closes or shuts.
4.
1 (def 2).
5.
an architectural screen or parapet, especially one standing free between columns or piers.
6.
Phonetics. an occlusion of the vocal tract as an articulatory feature of a particular speech sound.
Compare (def 5).
7.
Parliamentary Procedure. a cloture.
8.
Surveying. completion of a closed traverse in such a way that the point of origin and the endpoint coincide within an acceptably small margin of error.
Compare .
9.
Mathematics.

10.
Psychology.

11.
Obsolete. something that encloses or shuts in; enclosure.
verb (used with or without object), closured, closuring.
12.
Parliamentary Procedure. to .
/ˈkləʊʒə/
noun
1.
the act of closing or the state of being closed
2.
an end or conclusion
3.
something that closes or shuts, such as a cap or seal for a container
4.
(in a deliberative body) a procedure by which debate may be halted and an immediate vote taken See also cloture, guillotine, gag rule
5.
(mainly US)

6.
(geology) the vertical distance between the crest of an anticline and the lowest contour that surrounds it
7.
(phonetics) the obstruction of the breath stream at some point along the vocal tract, such as the complete occlusion preliminary to the articulation of a stop
8.
(logic)

9.
(maths)

10.
(psychol) the tendency, first noted by Gestalt psychologists, to see an incomplete figure like a circle with a gap in it as more complete than it is
verb
11.
(transitive) (in a deliberative body) to end (debate) by closure
n.

late 14c., “a barrier, a fence,” from Old French closure “enclosure; that which encloses, fastening, hedge, wall, fence,” also closture “barrier, division; enclosure, hedge, fence, wall” (12c., Modern French clôture), from Late Latin clausura “lock, fortress, a closing” (source of Italian chiusura), from past participle stem of Latin claudere “to close” (see close (v.)). Sense of “act of closing, bringing to a close” is from early 15c. In legislation, especially “closing or stopping of debate.” Sense of “tendency to create ordered and satisfying wholes” is 1924, from Gestalt psychology.

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 (“LaTeX as \subseteq and the upward closure of X in D is written \uparrow_\D X).
(1994-12-16)