This article has been updated.

Schools are closed, bars are shuttered and restaurants are take-out only. Gatherings have been limited in size, and many of us are working from home. It's all part of what’s called social distancing — and we've been doing it for long enough now that most people have come to understand exactly what that term means.

"Its kind of benign," said homeland security expert and WGBH News contributor Juliette Kayyem. "It has the language of care and comfort. We’re just gonna, sort of, distance you away from each other."

Social distancing, Kayyem said, is a term that comes to us from the world of public health and has been long used to describe strategies for combating the spread of contagious diseases.

Massachusetts Gov. Charlie Baker has repeatedly fielded questions about whether he will issue an order to shelter in place. During a press conference Monday morning, he outlined a "stay at home" advisory — not an order — which urges people to only leave their homes if essential.

"Everyone is advised to stay home and limit all unnecessary activities," Baker said.

Baker ordered all non-essential businesses in the commonwealth to cease physical operations, but said he would not issue an order for people to remain in their homes. Anyone who does go outside should observe social distancing, he said.

So, how does that differ from a shelter in place order?

"Shelter in place comes from the word of public safety and emergency management," Kayyem said. "And it means there’s something bad outside — a blizzard, a storm, terrorists at the Boston Marathon — and we need to keep you inside."

And while social distancing might sound "benign" and shelter in place fairly drastic, Kayyem said that in reality, they aren’t all that different.

Case in point the city of San Francisco, Calif., which has been under a shelter in place order for nearly a week. Residents there have been asked to stay inside except for essential activities.

"I actually went hiking yesterday," said Eric Meisel, a San Francisco resident, on Sunday. "And there were actually more people around than I thought I would see."

As in Massachusetts, all non-essential businesses have been ordered closed in San Francisco. In both places, the list of essential businesses extends beyond hospitals and grocery stores to include banks, hardware stores and even laundromats. Like in Boston, you can get take-out at some restaurants. And also like in Boston, you can go out for a hike. Meisel’s sister lives in Cambridge.

"I actually just talked to my sister and she was saying she's living pretty much the exact same life I am," he said. "It doesn’t seem too, too different."

Kayyem said that in general, governors or municipal leaders have the power to issue shelter in place orders, but not many tools to enforce them. And each looks a little different.

States like New York and Illinois have issued stay at home orders, while Massachusetts' is an advisory. But they look a lot like San Francisco’s shelter in place order — and frankly, not all that different from the social distancing measures already in place in the commonwealth. Some of these stay at home orders include the threat of civil fines for non-compliance, though none go quite as far as measures being taken in some European countries like Italy — or cities like Paris.

"You have to go out with this form that you sign," explained Paris resident Agnes Sire. "It’s a declaration on your honor, saying what you are doing outside."

The form states that you’re going out for one of a handful of essential reasons. Sire recently got a sense of how serious officials are taking things when she stopped to sit on a bench and drink her take-out coffee on her way home from a local food market.

"Some cops arrived and said, 'You can’t be there,'" Sire said. "I said, 'But I’m here alone with nobody next to me.' And they said no. It’s just because it's leisure and you have to understand that now, leisure is over."

She faced a €130 fine, but was let off with a warning.

That’s a little closer to what Kayyem said is the most drastic step governors in the U.S. could take — issuing a mandatory quarantine.

"Essentially, you are forced to stay in your home, and there’s the use of the military or police to keep you in your home," Kayyem said.

Short of a mandatory quarantine, Kayyem said that the myriad of terms we’re hearing are essentially fungible.

"We know what we need to do," she said. "You can call it sheltering in place or social distancing or lockdown or whatever you want. We need to keep people away from each other for a short period of time. Because if you look at the numbers in Paris and Germany and Italy, they’re terrifying."