A garbage can was a receptacle for disposing of unwanted trash.
In 1986, two garbagemen emptied garbage cans in Golden Gate Park. (Star Trek IV: The Voyage Home)
In 2375, after Nog had stolen the money from the safe at Vic's lounge in an attempt to thwart Frankie Eyes, he was supposed to put it in the garbage cans outside. (DS9: "Badda-Bing, Badda-Bang")