Despite its significant role in every level of education, the definition of the Science, Technology, Engineering, and Mathematics movement, or STEM, has remained elusive, becoming so vaporous as to provide little meaning. As education organizations navigate the STEM institution, they must collectively make sense of its norms, goals, and practices. Yet little is known about this process, including what sense is made, contributing factors, and implications. This paper describes a study guided by relational ethnography conducted in one K-8 school community that investigates how its members make sense of the STEM institution through cycles of interpretation and action. Sensemaking is investigated through interviews, concept maps, and surveys conducted with nine teachers, administrators, and external partners in the community along with analysis of school and external organization documents. Results are organized around three themes: the external nature of STEM, the process of sensemaking, and collective sensemaking in partnerships. First, the tension between the messy, amorphous institution of STEM and the organizational and personal context of teachers, disciplines, school, and community is described. It is proposed that the interpretation of STEM as external to the local context may contribute to a problem of curriculum narrowing, whereby aspects of disciplinary instruction, namely higher-order thinking skills, are also omitted. Second, four key factors influencing sensemaking of STEM are demonstrated: individual frames, disparate messaging from the environment, collaboration, or the lack thereof, and external partnerships. The factors are shown to provide dual obstacles to implementation of STEM as well as to contextual, collective sensemaking about STEM. Third, an investigation of external partnerships provide evidence for the institutions' messy and inequitable qualities. The paper concludes with a theory that resistance to STEM implementation demonstrated by study participants suggests problems lie not with a lack of clear institutional messages, but with an understanding by teachers that STEM, as presented, has little to do with their practice. Therefore, efforts to use STEM as a vehicle for implementing standards-based practices like higher-order thinking skills may be problematic. The paper concludes with proposals for research understanding the conflict between STEM and contextual, disciplinary practice, including epistemological and structural tensions. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]