The ship's store was a location aboard Federation starships set aside for items usually not carried in the cargo bays. Such items included apparel, tools, and samples of compounds. On a Galaxy-class starship, ship's stores were located on deck four.
In 2266, aboard the USS Enterprise, Charlie Evans gave a gift of perfume to Yeoman Janice Rand. As this perfume wasn't available from ship's stores, she asked Evans where he got it. (TOS: "Charlie X")
In early 2364, aboard the USS Enterprise-D, Lieutenant Natasha Yar went to ship's stores for sexy sleepwear. She was later seen in this sleepwear when seducing Lieutenant Commander Data. (TNG: "The Naked Now")
Later that year, Lore retrieved a macrotool and samples of quadratanium from the Enterprise store. With his possessions, Lore knocked out his 'brother' Data with a combination of champagne and quadratanium, and repaired his face with the macrotool. He turned the tool on Data causing damage to his face. (TNG: "Datalore")
A ship's store was also located on the Promenade of Deep Space 9. This store specialized in selling and repairing starship components. During the Occupation of Bajor, it was the site of the chemist's shop. (DS9: "Necessary Evil")