| 释义 |
knock-on, n. and a.
[f. the vbl. phr. to knock on: see knock v., esp. sense 13.]
A. n. (ˈknock-ˈon.) Rugby Football. The act of knocking the ball forward or ‘on’: see knock v. 13.
1845,1881[see punt n.3 1]. 1888Daily News 5 Oct. 5/2 A knock-on gives a free kick. 1905Daily Chron. 29 Dec. 9/5 The alleged incident of the referee in the New Zealanders–Newport match sounding the whistle when a knock-on by an All Black proved to the advantage of the Welsh team was..contrary to law. 1960Times 11 Jan. 17/1 A body of dedicated Scots thought that France's last [try] followed a knock-on. 1974Sunday Tel. 23 June 35/7 The referee did not see the knock-on.
B. adj. (ˈknock-on.)
1. Physics. Ejected, produced, or caused as a result of the collision of an atomic or sub-atomic particle with an atom.
1940Nature 13 July 65/2 A few particles of energy greater than 108 ev...were therefore considered to be mesons responsible for the production of ‘knock on’ showers. 1953Jrnl. Brit. Interplanetary Soc. XII. 203 These [sc. nuclear fragments] may be accompanied by knock-on particles (or shower particles) which also move with velocities comparable to the original particle. 1967A. H. Cottrell Introd. Metall. ii. 14 There are three main types of radiation damage... (3) Knock-on damage in which atoms inside the material are knocked from their sites by the impacts of nuclear particles. 1971Nature 6 Aug. 422/2 Knock-on protons produced by 3MeV neutrons would not..produce visible flashes.
2. Designating a mechanical part (e.g. of a vehicle) that may be attached or fastened by knocking. Also absol.
1952Motor Manual (ed. 34) vii. 150 There are two principal types of wheel fastening. The less common, known as the knock-on, has at its centre a large nut with two lugs or projections. Ibid. p. x, Knock on wheel fastening. 1959Times 12 Sept. 3/3 Moss's car has knock-on wheels. 1965Punch 20 Oct. 567/2 The imitation knock-on hubs had been knocked off by genuine thieves. 1967I. Hamilton Man with Brown Paper Face ii. 24 The strengthened knock-on wire wheels were original M.G.
▸ attrib. Chiefly Brit. Being a secondary or indirect consequence of another action, occurrence, or event; knock-on effect n. a secondary, indirect, or cumulative effect.
1972Times 18 Apr. 2/3 They would be more than willing to move towards a minimum wage of about {pstlg}20 a week..if they could be assured..that there would be no ‘knock-on effect’ in the differentials demanded by the rest of the labour force. 1983Listener 24 Nov. 4/3 The knock-on effect of losing the surface plankton life might prove crucial. 1990Internat. Freighting Weekly (Nexis) 13 Aug. 1 The ruptured trade relations between Iraq and Britain have knock-on consequences for the repayment of loans. 2000Z. Sardar Consumption of Kuala Lumpur 191 The financial system of Thailand went into collapse and the knock-on effect rippled across the region. |