The phrase "at a locker" is correct and usable in written English.
It can be used to indicate a specific location where a locker is situated, often in contexts related to schools, gyms, or public facilities.
Example: "I left my backpack at a locker near the entrance of the gym."
Alternatives: "in a locker" or "by a locker".
Junkin sat at a locker afterward, tears in his eyes.
He dresses, after all, at a locker with its own full-length cabinet, the one marked by a sticker depicting himself in mid-delivery, inside a Batman logo.
Smith, who was dressing at a locker next to Manning, said: "He has a lot on his plate but he keeps a cool head.
Jonathan Toews is not only the team captain, he's also an elder statesman at 22. "We know what it takes to win," Toews said, looking around at a locker room full of strangers, "and we've got the talent to do it".
The denouement of Mr. Sater's career on Wall Street began in 1998 at a locker at a Manhattan Mini Storage in SoHo, where investigators discovered two pistols, a shotgun and a gym bag stuffed with a trove of documents outlining the money laundering scheme and offshore accounts of Mr. Sater and his partners.
Gonzalez: Ordering online and picking the item up in-store (or at a locker) has definitely become more popular.
"I know it's going to be rough," he said to the crowd in a speech that sounded at times like a locker room pep talk.
How do you personalize the things you bring to, or have at, school — whether a locker, uniform, backpack, binder, or desk?
Coin-operated airport lockers still are available at some airports abroad, but they mostly disappeared at domestic airports after a terrorist explosion in a locker at La Guardia in 1975 killed 11 and injured more than 70.
Look for friendly people in class, at lunch, at your locker (or if you don't have a locker, then at your desk).
Frisbee opens a locker at Waterloo Station.
