When New York went into lockdown last spring to help stem the spread of the coronavirus, it was a rough time for Judy Fein, a retired psychotherapist who lives alone in an Upper East Side co-op.

“It wasn’t just my children I couldn’t see easily during the pandemic,” Ms. Fein, 74, said. “I love to have dinner parties and I use my apartment for fund-raisers, and obviously I haven’t been able to do that. I was feeling socially deprived and I’m not very good on the phone. To me, that’s not socializing.”

Toward the end of May relief came in the form of a telephone call. On the line was Serga Nadler, a fellow widow who lives down the hall, wondering if perhaps the two of them could take a walk together. Ms. Fein was surprised — she knew her neighbor only slightly — but delighted.

One stroll led to another and another. Ms. Nadler, 79, whose apartment includes outdoor space — a boon during Covid — eventually invited Ms. Fein for dinner on her terrace. Shared meals became a regular thing. The women began exchanging Netflix recommendations, successfully dieted together (that is, until they started taking advantage of outdoor dining) learned each other’s life story, felt safe in each other’s presence.

“There was a big void in my life, and when Serga and I got together it solved many things,” Ms. Fein said. “I think she was starved for friendship and so was I.”

For those who have scrupulously quarantined and who have similarly cautious (or geographically distant) close friends and family, the pandemic has been a lonely business. And Zoom, even for the Baby Zoom generation, is satisfying only up to a point.

Neighbors are proving to be a salvation for some, according to a study by Improvenet, an online company that helps homeowners manage remodeling projects.

Nearly 70 percent of the survey’s 2,500 respondents from around the country said they had gotten to know their neighbors better during the pandemic and 25 percent reported frequently socializing with their neighbors. Meanwhile, 57 percent said neighbors have, at times, filled the void left by relatives and friends.

The people next door, it seems, can be much more than sitcom fodder.

“Before Covid you could be ‘just neighbors,’” said Rachael Woldoff, a professor of sociology at West Virginia University and the author, with Robert C. Litchfield, of the just-published book “Digital Nomads: In Search of Freedom, Community, and Meaningful Work in the New Economy.”

“You’d say ‘hi,’ if you saw the person next door out early in the morning, you’d pick up your newspaper, go back inside and get ready to leave for work,” Ms. Woldoff continued. “It’s also possible that you would never have seen each other at all. But the more you’re at home — and people are likely to be home more now because they’re working remotely — the greater the possibility that you’re going to interact with the neighbors.”

Leslie Alexander, 71, and her husband Lenny, 74, don’t typically spend much time at home, a saltbox colonial on an acre and a half in Oxford, Conn. They are members of several museums in the area, have subscriptions to the symphony and to Long Wharf Theater in New Haven, and have never met a flea market or antiques shop they don’t like. “And usually, we take two major trips a year,” said Ms. Alexander, a retired elementary and middle school principal.

But with the arrival of the pandemic, home was where you would find the Alexanders; it was the only place you would find them. That’s how they morphed from acquaintances to close friends with Erik Granato and Jennifer Camarro, the 40-something couple down the road. Mr. Granato had met the Alexanders at a yard sale in 2019. He subsequently volunteered to mind their cats while they were on vacation in Europe.

“When Covid started to hit I think Jenn and Erik felt sorry that we were old,” Ms. Alexander said with a laugh. “Erik was good about volunteering to pick up groceries for us.” But what with one thing and another — they were the only Democrats on the road, they all loved cats — they happily formed a pod.

Ms. Alexander and Ms. Camarro planted gardens and shared the fruits of their labor. They began to bake bread, trading off loaves. At the end of the summer, Mr. Alexander helped Mr. Granato deal with an uncooperative swimming pool cover.

“We’ve become as close as any couple could be but I don’t think it would have happened to this extent without Covid,” Ms. Alexander said. “I think that to Jenn and Erik we’re in some way a substitute for the older generation. And to Lenny and me, they’re a substitute for our kids’ generation.” (Ms. Camarro’s parents live in Florida; Ms. Alexander has a daughter who lives near Austin and two sons who live in Brooklyn.)

Forming a relationship with the neighbors is, as much as anything, about opportunity, Ms. Woldoff said. Many of the common spaces in an apartment building are closed because of Covid, and “you’re not going to knock on doors,” she said, “which means the only way to run into a neighbor is if YOU decide you’re going to go to the store or take your dog for a walk. The degree to which an area is walkable is important for serendipitous meetings.”

Actually, some people DO knock on doors. A few months ago, Cornelia Holzbauer was on the elevator of her Williamsburg rental with, Caroline Marks, a woman who lived next door. “I’m very social so we chatted until we got to our floor,” said Ms. Holzbauer, 25, a freelance writer for an Austrian newspaper.

A few hours later, en route to the roof deck with one of her roommates, “I don’t know what possessed me but I knocked on Caroline’s door to see if she wanted to join us,” said Ms. Holzbauer. She did, said Ms. Holzbauer, “we connected from the get-go.”

Since then, the two have gotten together almost every day. “I’m very busy with my job and she’s in law school so she has a lot of work but we still get to hang out. Because we’re neighbors it’s easy. Even if we only have half an hour we can go for a walk.”

Outdoor space is very useful terrain for turning neighbors into pandemic friends. Just ask David Mbonu, a high school chess teacher who moved from Atlanta to New York in late February and settled in a three-unit apartment building with a back yard in Williamsburg.

“At first I took a lot of walks because I didn’t know anyone here,” Mr. Mbonu, 25, said. “But one night I decided to have dinner in the yard and I saw two guys eating back there too.” He went over, introduced himself and learned that they lived next door to him.

“It turned out that like me, one of the guys had a deeply religious Christian upbringing,” Mr. Mbonu said. “We discussed what it was like, and how to work with those beliefs in the world. We’re like bros now.”

A hunk of outdoor space proved similarly useful to Michael X. Heiligenstein, a cybersecurity blogger, who moved across the country from New York this past February, arriving in Los Angeles one day before a lockdown went into effect.

Fortunately, the one-bedroom apartment he rented came with a porch, an ideal perch to work, to enjoy a late afternoon glass of wine and to observe the passing scene.

“I would try to get a sense of people’s routines,” said Mr. Heiligenstein, 31. “I’d see who was heading out to go running. I started saying ‘hi’ a little bit, and invited a neighbor to come by for a beer. Then we started to talk to a couple who lives in the building across the way and we planned a cookout around Memorial Day.” They have since instituted a socially distanced Friday movie night.

“In the past, I met my friends through work and different activities,” Mr. Heiligenstein said. “But with the coronavirus, meeting people in proximity makes sense. There’s more opportunity not just to say hello to people but to have it evolve into something more.”

Sometimes, all this evolving requires a willingness to overlook the fact that the neighbors can’t seem to quit their leaf blower or adjust the volume on their favorite talk-radio host. It works both ways, of course. The people next door could well be working overtime to make allowances for your curious lawn signs.

In the pre-Covid era, those differences might have been a barrier to friendship, “but now you may be finding value in the neighbor,” Ms. Woldoff said. Perhaps, your children play with the neighbors’ children or they’re in the same pod at school. So you may think “I don’t agree with my neighbor about politics, but having our children play together for hours on end is more important.”

“Instead of having the freedom to pick people you have things in common with,” Ms. Woldoff added, “you’re doing things with people you don’t have things in common with, and maybe that’s a good thing.”

Last March, Lori Cheek took the coronavirus onslaught as her cue to leave New York, home for the last 25 years, and return to Kentucky where she was born and raised, and where she signed a one-year lease on an apartment in Louisville.

“When I first got back, I made a list of all the people I ever knew here who it wouldn’t seem crazy to reach out to,” recalled Ms. Cheek, 48, the founder and chief executive of a dating app. “I saw a few of them here and there, but it didn’t really work out. I couldn’t depend on them for companionship. They were all being careful and staying in their own little bubbles.”

She began aimlessly biking around town, “just doing all sorts of random things alone.” One day, she ended her ride at a table outside her building’s ground-floor pub, popped open her laptop and popped open a beer.

“You live here, right?” asked a man at a nearby table, an observant fellow tenant, it turned out.

Ms. Cheek thought of all the work she had to do. She thought about just how much she did not feel like chatting right then. She weighed those things against the fact that she knew no one in town, that the pandemic wasn’t really working in her favor.

She allowed the stranger to join her, but “I told him he had to sit six feet away — and we’ve been big buds ever since,” Ms. Cheek said. “We spend at least two hours a day talking together.”

Who would have thought it? Certainly not Ms. Cheek who’s a Democrat while her new friend, Chris Millay, 56, who works in IT for the Army, is a Trump supporter. She’s a city slicker; he’s anything but. Then there’s this: She’s a Kentucky Wildcats fan; he roots for its longtime rivals, the Louisville Cardinals.

“Around here that’s reason enough not to be friends with someone,” Ms. Cheek said. “It’s crazy that I’ve become so close to this man. I’ve met his dog, I’ve met his ex-wife. We’ve shared things with each other that we haven’t shared with other people.” For the record, all of this sharing is done outdoors.

Ms. Cheek thinks that she has made Mr. Millay appreciate the value of masks. Mr. Millay, meanwhile, has made Ms. Cheek re-evaluate her criteria for friendship. She’ll sometimes even put on a Louisville cap when the two of them are watching football games.

“I would never have known him if it weren’t for the pandemic,” Ms. Cheek said. “But now I love him, I really do, and I don’t think I’ll be able to shake him when all this is over.”

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