adv

• (interrogative) To what degree or extent.
  "How often do you practice?"
• (interrogative) In what manner:
  "Economics is a messy discipline: too fluid to be a science, too rigorous to be an art. Perhaps it is fitting that economists’ most-used metric, gross domestic product (GDP), is a tangle too.[…]But as a foundation for analysis it is highly subjective: it rests on difficult decisions about what counts as a territory, what counts as output and how to value it. Indeed, economists are still tweaking it."
• (interrogative) In what manner:
  "How do you solve this puzzle?"
• (interrogative) In what manner:
  "How should I know whether he likes raisins or not? Ask him!"

conj

• (informal) That, the fact that.
  "She told me how her father was a doctor."

noun

• (dialectal) An artificial barrow or tumulus; in later folklore, associated with fairies.
  "Fianlly, as regards the places in which these rites and mysteries may have been held, certain writers believe them to have been the "Fairy Hills" or "howes" in various parts of Scotland."
• (dialectal) In northern England, a low hill.

noun

• (World War II era, joint US/RAF) radiotelephony clear-code word for the letter H.