Watch the Weather Channel's Ari Sarsalari explain the Atlantic storm we call a "nor'easter."

Shortening of "north" to "nor" is at least as old as 1594, as demonstrated in "The Seaman's Secrets" by John Davis published that year.

For the crossword composer, "nor'easter" has pretty useful consonant/vowel alternation, and the letters used to spell "nor'easter" are seven of the top eight most used letters in the New York Times Crossword (thanks, Nathan).