| 释义 |
‖ addendum|əˈdɛndəm|
Pl. addenda |əˈdɛndə|.
[a. L. addendum something to be added, gerundive of add-ĕre to add. The pl. was in earlier use than the singular; cf. miscellanea, minutiæ, etc.]
a. A thing to be added; an appendix or addition. Also occas. in pl. form with sing. construction: a set of addenda (esp. one appended to a book).
1794Burns Wks. IV. 179 You cannot, in my opinion, dispense with a bass to your addenda airs. 1830Miss Mitford Our Village iv. (1863) 260 The addenda of the work. 1879O. W. Holmes Motley xxi. 179 After I had gone over the instructions for the last time I wrote an addendum. 1879Daily News 16 Apr. 3/6 The mover of the resolution accepted as an addendum thereto the further expression of opinion that, etc. 1840W. Berry Encycl. Heraldica IV. 1 The following Addenda has therefore been arranged in the same manner. 1936S.P.E. Tract XLV. 192 A catalogue, issued in the autumn of 1935 by one of the leading American university presses, mentions, as one of the merits of a certain book, that it contains an invaluable addenda. 1984Mech. Engin. CVI. 89/1 This addenda consists of 49 independent revisions.
b. Mech. A term applied to certain dimensions of toothed gearing (see quots.).
1841R. Willis Princ. Mechanism 98 Now this addition to the radius of the pitch circle [of a gear] is called by clock⁓makers the addendum, which term I shall, for convenience, employ. 1873Rankine & Bamber Mech. Text Bk. ii. ii. 81 The radius of the pitch circle of a circular wheel is called the geometrical radius; that of a circle touching the crests of the teeth is called the real radius; and the difference between these radii, the addendum. 1954Gloss. Terms Toothed Gearing (B.S.I.) 11 Addendum. 1. Of a helical or spur gear. a. Reference addendum, the radial distance from the reference cylinder to the tip cylinder. b. Working addendum, the radial distance from the pitch cylinder to the tip cylinder. 2. Of a wormwheel. Half the difference between the diameter of the pitch circle and the throat diameter. 3. Of a bevel gear. The distance from the pitch circle to the tip cone, measured on the back cone. |