assiduity
Great and persistent toil or effort.
countable, uncountable
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[…]
Constant personal attention, solicitous care.
countable, uncountable
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.
Where it comes from
From Latin assiduitas, from Latin assiduus. Equivalent to assiduous + -ity.
Adapted from the Wiktionary entry assiduity (CC BY-SA 4.0).