When I refer to old temples or shrines in Japan, shoule I use structures or buildings? I refer to each of them as a shrine or a temple, but when I want to generalize, like all these temples, shrines, walls or whatever in certain place, which were built hundreds years ago, how should I call them? To me, "buildings" sound like things built in this modern era. So I thought structures would be better, but sometimes I've heard people use "buildings" for that. I researched these words myself, but I'm not sure. Could you please explain the difference between two and which is the better word choice here?
A building generally is designed with walls and a roof. There certainly can be ancient buildings. Structures can be anything that is composed of structural components- a cell structure, a shade structure, etc. My advice is use building only when the referent was at least designed with walls and a roof- even if they have long since fallen in or washed away, and then only if your intent in the usage is to treat it as a whole entity whose basic nature is to have walls and a roof. Use structure when you wish to refer to something that does not walls and a roof or when referring to a building's structural components or design rather than its essence as a closed containing structure.
This building was erected in 100 BC. - We're talking about the whole thing as a building.
This structure has stood for thousands of years - Might be a building or just a bunch of pillars, but we are talking about it's fortitude as a structure.
This building was designed to hold the King's library. The structure's entrance is made of beams 6 feet wide. - We can switch back and forth on what we call it based on what we're saying about it
Interesting question. I would say that building is a common generic hypernym for such structures, and you could describe the places you mention as buildings.
However, you've correctly identified a problem with that word: it's too generic. The word building can be applied to office buildings, strip malls, houses, schools, temples, hotels, factories, stables, arenas, and restaurants. So, it's not very descriptive at all, and I don't think the word structure helps in that regard.
With that in mind, then, I would call the temples and shrines you mention places of worship. At least that word – which has its own entry in many dictionaries – narrows down the particular kind of building.
If you want to emphasize that these places of worship have been standing for hundreds of years, I would use the adjective ancient. So, here's how I would say it:
Last week, we visited many ancient places of worship.
Incidentally, I checked a few places in the thesaurus, and I could find no English word that, by itself, meant "old building." There's the word ruins, but that describes the physical state of a structure more than its age. Some words carry overtones of a probable long existance – such as castle – but castles still can be built today. I can't think of any way to emphasize that the structures have been standing for hundreds of years without using an adjective.
Generally speaking, a temple would be a fully-grown, human-accessible building, whereas a shrine may be as simple as a single statue, so could while it probably is a 'construction' it could NOT be called a building.
There are various terms you could use, depending on circumstances, such as "Religious site", "Holy site" etc but nothing comes to mind that is a single word.