(1) The fundamental structure of a system or organization. The basic, fundamental architecture of any system (electronic, mechanical, social, political, etc.) determines how it functions and how flexible it is to meet future requirements.
(2) Infrastructure may refer to system and development programs in contrast to applications. A computer system's infrastructure would include the operating system, database management system (DBMS), communications protocols, compilers and other development tools.
(3) In the world of AI, infrastructure refers to the huge datacenters required to develop large language models. See
AI datacenter.