push-downn.adj.

Brit.

/ˈpʊʃdaʊn/, U.S.

/ˈpʊʃˌdaʊn/

Origin: Formed within English, by compounding. Etymons: push v., down adv.

Etymology: < push v. + down adv., after to push down (see push v. 1b).

A. n.

1. Aeronautics. A manoeuvre in which an aircraft in level flight loses altitude and then resumes level flight. rare.

ΘΚΠ

society > travel > air or space travel > action of flying (in) aircraft > specific flying operations or procedures > [noun] > descent > and levelling out

push-down1938

1938 Jrnl. Royal Aeronaut. Soc. 42 625 The manœuvres consisted of push-downs and pull-ups from level flight..and push-ups from inverted flight.

2001 M. H. Gorn Expanding Envelope ii. 90 The flights..included..short, steep dives and abrupt pull-outs..; climbing turns from dives; and push-downs from shallow dives to imitate escape from pursuing enemies.

2. Computing and Linguistics. A push-down store or list (see sense B. 1). Also: an instance of storage of this kind.

ΚΠ

1961 Communications ACM 4 14/1 In many cases it is desirable to permit the accumulator to be the last cell in this push-down.

1976 H. Huwig in G. Goos & J. Hartmanis Math. Found. Computer Sci.: Proc. 5th Symp. 350 Encreasing time or tape bounds by a constant factor we can make the Turing machine using its tapes like pushdowns.

1999 Grammars 2 259 It is shown that the languages accepted by automata using concatenations of one–turn pushdowns can be characterized in terms of linear grammars with controlled derivations.

2005 S. Doraiswamy et al. in T. Härder & W. Lehner Data Managem. in Connected World vi. 105 The SQL compiler must decide on the right set of predicate pushdowns when complex predicates are issued against message queues.

B. adj.

1. Computing and Linguistics. Designating a linear store or list that receives and loses items at one end only, the first to be removed being always the last to have been added; relating to or employing such a store or list. Cf. LIFO n. b.

ΘΚΠ

society > computing and information technology > data > [adjective] > data structure

push-down1959

threaded1960

balanced1962

machine-coded1964

push-up1966

1959 Preprints Papers 14th Meeting Assoc. Computing Machinery 35-4 This requires a push-down list for saving temporary storage.

1963 N. Chomsky in R. D. Luce Handbk. Math. Psychol. II. 343 Evidently pushdown storage is an appropriate device for accepting (generating) languages..which have..nesting of units (phrases) within other units.

1972 R. Quirk et al. Gram. Contemp. Eng. xi. 736 The wh-element can be fronted from a position in a clause subordinate to the wh-clause (a pushdown wh-element); for example the informal: I don't remember which shelf he told me I was to fetch it from.

1995 J. Wiles & J. Elman in J. D. Moore & J. F. Lehman Proc. 17th Ann. Conf. Cognitive Sci. Soc. 483 This language requires a pushdown store in order to keep track of the as in order that each a may be matched by a later b.

2004 E. S. Raymond Art of Unix Programming viii. 203 PostScript is a stack-based language; arguments of PostScript's primitive procedures (operators) are normally popped off a push-down stack of arguments.

2. That may be, or is designed to be, pushed down.

ΚΠ

1967 Daily Times-News (Burlington, N. Carolina) 9 Nov. Musical typewriter..The push-down keys activate striking arms that hit the true tone notes.

1977 Custom Car Nov. 18/1 The Escort has sprouted chrome push-down bonnet catches.

1984 Sears, Roebuck Catal. Spring–Summer 39 Pastel pushdown socks are woven of mercerized cotton and stretch nylon.

2003 N.Y. Times (National ed.) 7 Dec. i. 26/2 You know those push-down soap dispensers? Well, allegedly someone put some of the product in one of those in the men's bathroom.

This entry has been updated (OED Third Edition, December 2007; most recently modified version published online March 2022).

单词	push-down
释义	push-downn.adj. Brit. /ˈpʊʃdaʊn/, U.S. /ˈpʊʃˌdaʊn/ Origin: Formed within English, by compounding. Etymons: push v., down adv. Etymology: < push v. + down adv., after to push down (see push v. 1b). A. n. 1. Aeronautics. A manoeuvre in which an aircraft in level flight loses altitude and then resumes level flight. rare. ΘΚΠ society > travel > air or space travel > action of flying (in) aircraft > specific flying operations or procedures > [noun] > descent > and levelling out push-down1938 1938 Jrnl. Royal Aeronaut. Soc. 42 625 The manœuvres consisted of push-downs and pull-ups from level flight..and push-ups from inverted flight. 2001 M. H. Gorn Expanding Envelope ii. 90 The flights..included..short, steep dives and abrupt pull-outs..; climbing turns from dives; and push-downs from shallow dives to imitate escape from pursuing enemies. 2. Computing and Linguistics. A push-down store or list (see sense B. 1). Also: an instance of storage of this kind. ΚΠ 1961 Communications ACM 4 14/1 In many cases it is desirable to permit the accumulator to be the last cell in this push-down. 1976 H. Huwig in G. Goos & J. Hartmanis Math. Found. Computer Sci.: Proc. 5th Symp. 350 Encreasing time or tape bounds by a constant factor we can make the Turing machine using its tapes like pushdowns. 1999 Grammars 2 259 It is shown that the languages accepted by automata using concatenations of one–turn pushdowns can be characterized in terms of linear grammars with controlled derivations. 2005 S. Doraiswamy et al. in T. Härder & W. Lehner Data Managem. in Connected World vi. 105 The SQL compiler must decide on the right set of predicate pushdowns when complex predicates are issued against message queues. B. adj. 1. Computing and Linguistics. Designating a linear store or list that receives and loses items at one end only, the first to be removed being always the last to have been added; relating to or employing such a store or list. Cf. LIFO n. b. ΘΚΠ society > computing and information technology > data > [adjective] > data structure push-down1959 threaded1960 balanced1962 machine-coded1964 push-up1966 1959 Preprints Papers 14th Meeting Assoc. Computing Machinery 35-4 This requires a push-down list for saving temporary storage. 1963 N. Chomsky in R. D. Luce Handbk. Math. Psychol. II. 343 Evidently pushdown storage is an appropriate device for accepting (generating) languages..which have..nesting of units (phrases) within other units. 1972 R. Quirk et al. Gram. Contemp. Eng. xi. 736 The wh-element can be fronted from a position in a clause subordinate to the wh-clause (a pushdown wh-element); for example the informal: I don't remember which shelf he told me I was to fetch it from. 1995 J. Wiles & J. Elman in J. D. Moore & J. F. Lehman Proc. 17th Ann. Conf. Cognitive Sci. Soc. 483 This language requires a pushdown store in order to keep track of the as in order that each a may be matched by a later b. 2004 E. S. Raymond Art of Unix Programming viii. 203 PostScript is a stack-based language; arguments of PostScript's primitive procedures (operators) are normally popped off a push-down stack of arguments. 2. That may be, or is designed to be, pushed down. ΚΠ 1967 Daily Times-News (Burlington, N. Carolina) 9 Nov. Musical typewriter..The push-down keys activate striking arms that hit the true tone notes. 1977 Custom Car Nov. 18/1 The Escort has sprouted chrome push-down bonnet catches. 1984 Sears, Roebuck Catal. Spring–Summer 39 Pastel pushdown socks are woven of mercerized cotton and stretch nylon. 2003 N.Y. Times (National ed.) 7 Dec. i. 26/2 You know those push-down soap dispensers? Well, allegedly someone put some of the product in one of those in the men's bathroom. This entry has been updated (OED Third Edition, December 2007; most recently modified version published online March 2022). < n.adj.1938
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