Definition of "secular"

In this event, the s ϕ ( k ) {\displaystyle s\phi (k)} curve in Fig. 15.5 will be subject to a secular upward shift, resulting in successively higher intersections with the λ k {\displaystyle \lambda k} ray and also in larger values of k ¯ {\displaystyle {\bar {k}}} .

2005, Alpha Chiang and Kevin Wainwright, Fundamental Methods of Mathematical Economics (4th ed.), McGraw-Hill International, p. 501

The skewed distribution of productivity gains is thus less a new phenomenon than a secular trend.

2006, “Economics focus: Dividing the pie”, in The Economist‎

The long reaches that were like one and the same reach, monotonous bends that were exactly alike, slipped past the steamer with their multitude of secular trees looking patiently after this grimy fragment of another world, the forerunner of change, of conquest, of trade, of massacres, of blessings.

1899 April, Joseph Conrad, “The Heart of Darkness”, in Blackwood’s Edinburgh Magazine, volume CLXV, number MII, New York, N.Y.: The Leonard Scott Publishing Company, […], part III (Conclusion)

Laplace (1749–1827) "saved the world" by using probability theory to estimate the parameters accurately enough to show that the drift of Jupiter was not secular after all; the observations at hand had covered only a fraction of a cycle of an oscillation with a period of about 880 years.

2003, E. T. Jaynes, Probability Theory: The Logic of Science, Cambridge University Press, pages 234–235

The secular A and nonsecular B parts of hyperfine interaction for any particular frequencies να and νβ are derived from eqn.(21) by ...

2000, S. A. Dikanov, Two-dimensional ESEEM Spectroscopy, in New Advances in Analytical Chemistry (Atta-ur-Rahman, ed.), page 539

On further examination, I found the clergy, in general, persons of moderate minds and decorous manners : I include the seculars, and the regulars of both sexes

1790 November, Edmund Burke, Reflections on the Revolution in France, and on the Proceedings in Certain Societies in London Relative to that Event. […], London: […] J[ames] Dodsley, […]