Systems and IT architecture is different than building architecture but the main idea is the same. Architects design and specify how a system is to be built to meet the demands of a organization. They make the important decisions up front about what the system will do and the main technologies that will be used to implement it. The architects stay around during the development phase ensuring that the developers and engineers build it according to their vision of what it should be.
Someone who architects systems.
Someone who architects a wide range of technology for an organization. Usually IT Architects rise from the ranks of Full-Stack Engineers because of their skills, abilities, and knowledge spanning the spectrum of applications development and systems operations.