Word of the day: watchword

The word of the day is watchword:

1. a word or short phrase to be communicated, on challenge, to a sentinel or guard; password or countersign.
2. a word or phrase expressive of a principle or rule of action; slogan
3. a rallying cry of a party, club, team, etc.

c.1400, "password," from watch (n.) in the military sense of "period of standing guard duty" + word. In the sense of "motto, slogan" it dates from 1738.

(http://dictionary.reference.com/browse/watchword)

"For almost two thousand years, China's numbers had grown very slowly.  That changed in the decades after the violent Qing takeover.  From the arrival of American crops at the beginning of the new dynasty to the end of the eighteenth century, population soared.  Historians debate the exact size of the increase; many believe the population roughly doubled, to as much as 300 million people.  Whatever the precise figure, the jump in numbers had big consequences.  It was the demographic surge that transformed the nation into a watchword for crowding."

  - Charles Mann, 1493: Uncovering the New World Columbus Created