Though her late conversation with her daughter-in-law had made her resolve on remaining at Norland no longer than was unavoidable, it had not produced the smallest effect on her in that point to which it principally tended.
What I am now doing indeed, seems nothing at all, since it can advance him so little towards what must be his principal, his only object of happiness.
Mrs. Jennings, knowing nothing of any change in the patient, went unusually early to bed; her maid, who was one of the principal nurses, was recreating herself in the housekeeper’s room, and Elinor remained alone with Marianne.
…ill-disposed, from the state of her spirits, to be pleased with the Miss Steeles, or to encourage their advances; and to the invariable coldness of her behaviour towards them, which checked every endeavour at intimacy on their side, Elinor principally attributed that preference of herself which soon became evident in the manners of both, but especially of Lucy, who missed no opportunity of engaging her in conversation, or of striving to improve their acquaintance by an easy and frank…
Mrs. Dashwood, whose eyes, as she answered the servant’s inquiry, had intuitively taken the same direction, was shocked to perceive by Elinor’s countenance how much she really suffered, and a moment afterwards, alike distressed by Marianne’s situation, knew not on which child to bestow her principal attention.
The selfish sagacity of the latter, which had at first drawn Robert into the scrape, was the principal instrument of his deliverance from it; for her respectful humility, assiduous attentions, and endless flatteries, as soon as the smallest opening was given for their exercise, reconciled Mrs. Ferrars to his choice, and re-established him completely in her favour.
—She was already greatly displeased with Mrs. Ferrars; and such ill-timed praise of another, at Elinor’s expense, though she had not any notion of what was principally meant by it, provoked her immediately to say with warmth, "This is admiration of a very particular kind!
There are no more uses of "principal" in the book.
Show samples from other sources
The principal idea is that decisions should be made by the people who are most knowledgeable about specific circumstances that impact the decision.
The singer was the principal performer; though the whole band was good.