How, adv.
[A-S. hū, hwā, hwȳ, hwǣ, properly instrum. of hwā, hwæt, who, what, pron. interrog., D. hoe, O. Sax. hueo, O. H. Ger. hweo, N. H. Ger. wie, Goth. hvaiva.]
Sense 1. In what manner or way; by what means.
How can a man be born when he is old? John iii. 4.
Sense 2. To what degree or extent; in what proportion; by what measure or quantity.
O, how love I thy law! it is my meditation all the day. Ps. cxix. 97.
By how much they would diminish the present extent of the sea, so much they would impair the fertility, and fountains, and rivers of the earth. Bentley.
Sense 3. For what reason; from what cause.
How now, my love! why is your cheek so pale? Shak.
Sense 4. In what state, condition, or plight.
How, and with what reproach, shall I return! Dryden.
How is used in each sense, interrogatively, interjectionally, and relatively; it is often employed by itself, as an interrogation, interjection, or exclamation. “How are the mighty fallen!” 2 Sam. i. 27. With a following that, it is superfluous, and no longer in good use.
Thick clouds put us in some hope of land: knowing how that part of the South Sea was utterly unknown. Bacon.