Definition of "diminution"

Another part, feeling a diminution of confidence in him, still hope that the general tenor of his conduct will be essentially right.

1800 October 24, Alexander Hamilton, “Letter from Alexander Hamilton, Concerning the Public Conduct and Character of John Adams, Esq. President of the United States”, in Harold C. Syrett, editor, The Papers of Alexander Hamilton‎, volumes 25, July 1800 – April 1802, New York: Columbia University Press, published 1962, page 187

Cold is usually shapeless, I suppose, extending over large spaces equally, or with gradual diminution.

1860, John Ruskin, chapter 1, in Modern Painters, volumes V (parts VI–IX), London: Smith, Elder, and Co., […], § 9, page 111

Scenic illusions such as those caused by the haze, or the apparent diminution of scale where everything was enormous, intrigued Dutton.

1954, Wallace Stegner, Beyond the Hundredth Meridian: John Wesley Powell and the Second Opening of the West, Houghton Mifflin, page 170