| 释义 |
▪ I. approximant, n.
Brit. |əˈprɒksɪm(ə)nt|, U.S. |əˈprɑksəm(ə)nt|
[‹ approxim- (in approximate v.) + -ant suffix1, after discriminant n., interpolant n., etc. Compare earlier approximant adj.]
1. Math. An approximation to the solution of a given problem (whether a function, a series, etc.).
1903E. B. Van Vleck in Trans. Amer. Math. Soc. 4 325 Such a fraction I shall term an approximant and denote by Upg/Vpq. Padé arranges all the approximants in a table of double entry. 1956F. B. Hildebrand Introd. Numerical Anal. ix. 396 Since (9.99) is an identity..terminating the fraction with an ..will give a function rn + 1(x)... The result of this termination may be called the (n + 1) th convergent (or approximant). 1995Ann. Appl. Probability 5 1 Taking an upper Riemann approximant and using the fact that the renewal measure is uniformly bounded on intervals of fixed length shows that [etc.].
2. Phonetics. A sound produced by the frictionless passage of breath through a narrow opening between two articulators, as in the English consonants r and w, formed by bringing the tongue and lips close without actually touching.
1964P. Ladefoged Phonetic Study W. Afr. Lang. vi. 25 The term approximant is used here to describe a sound which belongs to the phonetic class vocoid or central resonant oral, and simultaneously to the phonological class consonant in that it occurs in the same phonotactic patterns as stops, fricatives and nasals. 1982J. C. Wells Accents of English i. 75 Most accents use a post-alveolar or retroflex approximant for intervocalic /r/ in words such as very. 1997D. Crystal Dict. Linguistics & Phonetics (ed. 4) 24 In some analyses, [h] would also be considered an approximant (i.e. the voiceless equivalent of the vowel following).
▪ II. † aˈpproximant, a. Obs. rare—1.
[ad. L. approximānt-em pr. pple. of approximā-re: see next.]
Approaching closely, resembling.
1641Sir E. Dering Sp. on Relig. 21 June, Whereby our times might be approximant, and conformant to the Apostolicall..Church. |