This term, Architecture, is used for a few thousands of years, especially in big constructions, like The Great Wall of China, The Pyramids in Egypt, the roads structure built by the Roman Empire etc.
Nowadays, we use it when building something greater (notice the relative term) than usual things. We can speak about the Architecture of a big building or a big bridge, but we cannot speak on the Architecture of a small and simple house or bridge.
In Information Technology things are the same. We have huge IT systems with a designed Architecture, but nothing for the small IT applications.
So, what definition can we have for this IT Architecture? I think it is good enough something like IT Architecture is the art or science of designing and delivering valuable technology strategies.
Why am I so interested in this sector? Because I worked on a few architectures and I noticed the similarity of thinking in Business Analysis and IT Architecture: both professional need to think:
If you think the same, please find some useful details here:
Why business needs should shape IT architecture
Information technology architecture
What is Architecture?
and recommended practice here:
All About IEEE Std 1471
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