Definition of "assiduity"

During the whole time of his abode in the university he generally spent thirteen hours of the day in study; by which assiduity besides an exact dispatch of the whole course of philosophy, he read over in a manner all classic authors that are extant […]

1661, John Fell, The Life of the most learned, reverend and pious Dr. H. Hammond‎

With the most patient assiduity he peered into the intricacies of unrevealed structure. No object was too minute, none too large, for his attention.

1845, Jordan Roche Lynch, The Hunterian Oration, page 8

After a hurried and frugal meal we were introduced with loving assiduity upon the part of the manager to the contents of his engine-house, and to the miscellaneous scrap-heap of disused implements with which the grass was littered.

1929, Sir Arthur Conan Doyle, When the World Screamed‎

With difficulty could man be born into the world, or as soon as born would he die, leaving life at the very threshold of existence, unless the friendly hand of the careful matron, and the affectionate assiduities of the nurse, lent their aid to the helpless babe.

1559, translated by Thomas Paynell: Erasmus, The Complaint of Peace (1521)

I will stay even contrary to your wishes; and though you should persist to shun me, I will make my respectful assiduities atone for the levity of my past conduct.

1773, Oliver Goldsmith, She Stoops to Conquer

Disgusted with the insipid boastings of him who continued his unceasing assiduities to Miss Airey, without any advancement towards that issue doubtless anticipated by herself and friends—...

1838, [Letitia Elizabeth] Landon (indicated as editor), chapter XVI, in Duty and Inclination: […], volume II, London: Henry Colburn, […], page 226