When we talk about architecture, we are usually talking about buildings.
If we talk about the architecture of typical school, we might list the sort of rooms you would expect:
- science labs
- assembly hall
- library etc
We would also think about the floor plan - how they are connected by corridors, where the main entrance and fire exits should be.
This provides us with an overall pattern of how a school is designed. We could compare this with the architecture of, say, a hospital. It would have wards instead of classrooms, operating theatres instead of science labs, etc. But it would still have corridors, fire exits and a canteen.
If we then look at a particular school, we can see how the overall pattern is applied. For example, a small primary school might not have a gym and an assembly hall. It might just have a gym which can be used as a hall.
Computer architecture has a similar meaning. It covers the essential parts that are in almost all computers, in one form or another.