The contours of user experience (UX) design practice have been shaped by a diverse array of practitioners and disciplines, resulting in a difuse and decentralized body of UX-specifc disciplinary knowledge. The rapidly shifting space that UX knowledge occupies, in conjunction with a long-existing research-practice gap, presents unique challenges and opportunities to UX educators and aspiring UX designers. In this paper, we analyzed a corpus of question and answer communication on UX Stack Exchange using a practice-led approach, identifying and documenting practitioners’ conceptions of UX knowledge over a nine year period. Specifcally, we used natural language processing techniques and qualitative content analysis to identify a disciplinary vocabulary invoked by UX designers in this online community, as well as conceptual trajectories spanning over nine years which could shed light on the evolution of UX practice. We further describe the implications of our fndings for HCI research and UX education.