IBM on Architecture
What is a software architecture? https://www-128.ibm.com/developerworks/rational/library/feb06/eeles/index.html
They use the IEEE standard. I still prefer my definition: https://blogs.technet.com/michael_platt/archive/2006/03/27/423300.aspx
Characteristics of a Software Architect https://www-128.ibm.com/developerworks/rational/library/mar06/eeles/index.html
Again I think the MCA characteristics are better thought out and more measurable: