ˈturning-point
[f. turning vbl. n. + point n.]
1. lit. A point at which something turns, or changes its direction of motion, etc.; spec. a maximum or minimum point on a graph, where it begins to tend downwards or upwards.
| 1856 Stanley Sinai & Pal. xii. 400 Near what may be called the turning-point of its course, where its spacious stream is diverted..by the chain of Amanus. 1956 Railway Mag. Mar. 165/2 Katrane..is the only turning point (a triangle) for engines between Amman and Ma'an. 1977 Wandsworth Borough News 16 Sept. 9/3 London Transport should be asked to stop using Medfield-street as a turning-point for their buses. |
2. fig. A point at which a decisive change of any kind takes place; a critical point, crisis. (The usual sense.)
| 1836 J. Keble Wks. R. Hooker I. p. li, In the annals of the Church,..we may from time to time mark out what may be called turning points. 1851 Ruskin Arrows of Chace (1880) I. 86, I believe these young artists to be..at a turning-point, from which they may either sink into nothingness or rise to very real greatness. 1874 Parker Illustr. Goth. Archit. i. iii. 92 At this principal turning-point in the history of architecture. 1885 Athenæum 23 May 669/1 The turning-point from summer to autumnal weather. 1887 J. C. Morison Service of Man 8 One of those turning-points in the evolution of thought which mark the close of an old epoch. |
3. Surveying. A subsidiary bench-mark whose height above datum is determined during the operation of finding, by differential levelling, the difference of level of two permanent bench-marks.
So called because the graduated staff on which the height is read off is at this point turned round so as to be read from the permanent (or the next subsidiary) bench-mark.
| 1891 in Cent. Dict. |