and I thought they are different. Garbage were left-over from the kitchen or bathroom and trash was something like those old chairs, empty colour spray cans, old computers etc..

To my understanding, trash is "dry", i.e. paper, cardboard, plastic, etc. - the kind of stuff you would throw away in an office, for example. Garbage is "wet", i.e. food scraps and such - the kind of stuff you would throw away in your kitchen.