ISO 9241-210 defines user-experience as "a person's perceptions and responses that result from the use or anticipated use of a product, system or service". So, user-experience is subjective and focuses on the use.
In industry terms, it's a professional label for individuals who are skilled at creating software designs that are user-centric - focusing on feedback from user research, labs, web-metrics and testing to create a better experience for end-users. Normally, I just tell people we help design the the next generations of software and websites while also helping them function better than previous versions. For me, design architecture is a combination of user-experience, interaction design, user-interface design and information architecture. It's more than just the typical UX Design with some prototyping, but takes everything into the abstract, along with all the new features that stakeholders and sponsors wish to see, and target the correct audience while listening to feedback and designing the next digital evolution of software with an eye on both functionality and aesthetics.