‘Active shooter’ used to refer to sportsmen. Now you cringe when you hear it.

After Wednesday's shootings in Alexandria, Virginia and San Francisco, social media buzzed with phrases we now automatically associate with tragedy.

"Sheltering in place" because of an "active shooter situation" once might have sounded unfamiliar but, distressingly, now rings completely routine. "Another active shooter. Can't stand these damn situations," said one tweeter this past week; "another active shooter," a different user wrote, adding, "*pretends to be shocked*." A third Twitter user summed up the zeitgeist: "Active shooter situations becoming this normal should not be normal."

The phrases themselves are not new, but they've been normalized in ways that their original speakers would never have dreamed and that make their current users cringe.

"Active shooter" goes back at least a century and was once blandly literal: It referred to sportspeople who shot guns. Early uses are shockingly quotidian by modern standards. "It is understood that the duPont Club is going to stage a big watermelon shoot on August 21st, and this will no doubt serve to bring out most of the active shooters," reads one 1915 article about the annual Wilmington Trophy Shoot in Delaware. "On this date melon will be served."

The literal meaning (a sports or recreational shooter who is active) was the most common one given to the phrase "active shooter" for decades — well into the 1990s, in fact. News stories through the 1970s and 1980s about active shooters didn't touch on psychology, motive, political persuasion, history of violence or havoc wreaked, but instead on topics ranging from women who were active in gun clubs, the active shooter who chose trap shooting over hunting and why, and the cheerful camaraderie between civilian gun clubs and the police officers they practiced and took gun safety classes with.

In police parlance, however, an active shooter was not a gun club member. In the mid-20th century, an active shooter was anyone who discharged a firearm in the commission of a crime; by the 1970s, it referred to a shooter who was actively targeting a person or people. This meaning showed up occasionally in crime reports or action potboilers, though it stayed out of public view, for the most part, until April 1999. In the days following the Columbine High School shooting, the broader American public came to learn about what SWAT teams and police officers had long called active shooters.

This pivot point upon which the meaning of "active shooter" turned was so breathtakingly terrible that it signaled not only the beginning of a new range of police and civilian tactics, but also the end of the previous use of "active shooter." The meaning that referred to a sportsperson with a gun almost instantly disappeared.

The Columbine shooting also gave renewed prominence to an old phrase redolent of imminent disaster: "shelter in place." The phrase first saw use in government documents during the Cold War, when the threat of nuclear annihilation at the hands of the Soviets was ever nigh, though it wasn't widely used among the public. It initially referred to a physical shelter, but government jargon has a way of creeping out and taking on new life. By the 1970s and 1980s, "shelter in place" became an order issued to communities during other disasters, from hurricanes to chemical leaks. The pattern holds even post-Columbine. Shelter in place was one tactic police departments and the FBI suggested that schools take up in the event of an active-shooter situation.

It's worth noting that the protocol is morphing from shelter in place to "run, hide, fight." I know this because of the flyers posted in the office at my daughter's school; from her blase teenage recounting of school lockdowns (drills and otherwise); from the utterly bored way she says "lockdown," "shelter in place" and "active-shooter drills" as nonchalantly as she refers to "field hockey" and "french fries."

In 2014, the FBI released a report that said the average number of active-shooter situations per year had more than doubled between the period 2000-2006 and 2007-2013. We've become wanly accustomed to the nomenclature of mass shootings, but regardless of how common the terms surrounding these shootings are, we continue to grapple with the need for their existence. As I was writing this piece Wednesday, the day of the incidents in Alexandria and San Francisco, Twitter informed me that there was another nationally reported shooting, this time in New York, outside the Barclays Center; one man was wounded.

Then again: The term "mass shooting" was first used with its most common and current meaning (a shooting in which multiple people are injured or killed) in 1934. The event that triggered its use was an ambush at a parade that left three dead and 21 injured. It was a contentious midterm election year during Franklin D. Roosevelt's first term. The paraders were most likely Democrats; they were shot in Pennsylvania, a battleground state, the night before Election Day. A Democratic challenger beat a Republican incumbent in a groundswell of populist support for Roosevelt's New Deal. The scenario, and the words used to describe it, are sadly familiar.

Stamper is a lexicographer at Merriam-Webster and the author of "Word by Word: The Secret Life of Dictionaries."