Sedulous, a. — Webster enters it under “sedulous”
Etymology: [L. sedulus, perhaps from sedere to sit, and so akin to E. sit.]
Diligent in application or pursuit; constant, steady, and persevering in business, or in endeavors to effect an object; steadily industrious; assiduous; as, the sedulous bee. What signifies the sound of words in prayer, without the affection of the heart, and a sedulous application of the proper means that may naturally lead us to such an end L'Estrange.
Syn. -- Assiduous; diligent; industrious; laborious; unremitting; untiring; unwearied; persevering. -- Sed"u*lous*ly, adv. -- Sed"u*lous*ness, n.
Shades of meaning
Fernald has no entry of its own for sedulousness; he lists it under industry.
He lists it without comment; the entries above explain its neighbors.