There’s a lot of perspectives on how to define an abstract concept like this one. How you will define it, also depends on your knowledge and your experience in the subject.
Adolf Loos defined architecture with this quote: “If we find a mound six feet long and three feet wide in the forest, formed into a pyramid, shaped by a shovel, we become serious and something in us says, `someone lies buried here´. That is architecture”.
For Marcus Vitruvius, “Architecture is the art of building”.
In conclusion, we must know that Architecture is the summitry of Art and Technique, building, and construction. It also needs human life for its functionality and depending on the time, society and civilization will improve this Architecture.