noun

• (chiefly Commonwealth, sometimes derogatory) A native or inhabitant of the United States.
  "...in a short time, a kind of infectious mirth and pride in their bargains took possession of the place, and every one bought something, holding out their purchases to view, and praising them in the words and phraseology of the young yankees, who, finding their own importance, were not slow to avail themselves of it,..."
• (chiefly Southern US) A native or inhabitant of the Northern United States.
  "[…]so that I couldn't help telling her, sir, that in our country, leastways in Virginia (they say the Yankees are very pert), young people don't speak of their elders so."
• (chiefly Northern US) A native or inhabitant of New England.
• (chiefly southern Louisiana) An Anglo, as opposed to someone with French ancestry; a native or inhabitant of the rest of the United States.

verb

• (dated, slang, US, Canada, sometimes offensive) to cheat, trick or swindle somebody; to misrepresent something
  "Kentuckians reportedly regarded a Yankee “as a sort of Jesuit” because of his religious zeal, while in Illinois the term yankeed was synonymous with cheated."

noun

• (nautical) A headsail resembling a genoa or a jib but with a high-cut clew, normally used together with a staysail. A sailing boat is typically equipped with three yankee sails of different sizes, number one being the largest.
• (international standards) Alternative letter-case form of Yankee from the NATO/ICAO Phonetic Alphabet.