To brace oneself against pain or a difficult experience. This expression is believed to come from the days when those wounded in battle had to be treated without anesthesia and were made to bite on a lead bullet to brace themselves against the pain of surgery. Certainly this was the meaning in Rudyard Kipling’s The Light That Failed (1891): “Bite on the bullet, old man, and don’t let them think you’re afraid.” However, some authorities suggest that the term comes from the practice of gunners biting off the end of a paper-tube cartridge in order to expose the powder to the spark. In times of anesthesia and more sophisticated weaponry, biting the bullet became entirely figurative, as when P. G. Wodehouse wrote, “Brace up and bite the bullet. I’m afraid I have bad news” (The Inimitable Jeeves, 1923).

A fail-safe solution to a problem. The term was coined by Paul Ehrlich (1854–1915), who won the 1908 Nobel Prize in physiology or medicine. He gave the name to a compound that selectively targeted a bacterium without affecting other organisms, specifically the agent causing syphilis. The name soon was transferred to other curative compounds, and later to other kinds of problem. For example, “The Federal Reserve has no magic bullet for dealing with high unemployment.”

A highly accurate projectile of death or destruction. Sir Walter Scott may have been the first to use the idea of a literal silver bullet in Lockhart (1808), “I have only hopes that he will be shot with a silver bullet.” The term caught on in the first half of the 1900s because the popular western hero of the radio program, The Lone Ranger, used a silver bullet. During the Korean War an antiaircraft shell that hit precisely on target was called “silver bullet.” By the late 1900s the term also was being used figuratively, as in, “We’re hoping our new software will be the silver bullet to put the company on the map.”