Red Arch Solutions empowers mission-driven organizations by delivering innovative, scalable, and secure technical solutions. Our team thrives on collaboration, technical excellence, and accelerating our customers' growth goals. We are seeking a Principal Ontologist to support the deployment and integration of Progress Semaphore, a semantic AI platform, within a large-scale enterprise data modernization initiative. This role will focus on developing and applying ontologies to unify and enhance data across mission support domains such as human resources, logistics, acquisitions, and IT governance. The ideal candidate will bring deep expertise in knowledge representation, semantic technologies, and ontology engineering, and will collaborate with data architects, software engineers, and business stakeholders to ensure semantic consistency and interoperability across diverse data sources.