A garbage can is a waste receptacle for trash and other rubbish.
The actual "garbage cans" were originally galvanized metal containers with lids to keep pests and animals out. They resembled an oversized #10 tin in several ways, including indentations to help prevent can damage. One could always tell when the garbage men were taking away the trash because they tended to bang the empty cans around, making a ruckus and alerting families to send their kids out with last night's dinner scraps so they didn't end up causing an unpleasant smell.
These days folks use either common dumpsters or plastic refuse containers, sometimes with wheels. You can still purchase the original galvanized garbage cans but they tend to be used to store things like pet food in the garage.