Terminology, lexical meaning, and semantic analysis are central to linguistic science, as they enable a deep understanding of vocabulary structure and development. This article explores the nature of terms, their definitional and systemic functions, and their distinction from general vocabulary, with particular focus on pedagogical and scientific terminology. It highlights the principles of monosemy, context-bound usage, and systemic interrelations of terms, and examines examples from medicine, literature, linguistics, and pedagogy. Moreover, the study addresses the evolution of terms in response to social, technical, and scientific developments, the challenges of translation, synonymy, polysemy, and terminological standardization. The analysis emphasizes that lexical-semantic study of terms enhances conceptual clarity, supports interdisciplinary connections, and strengthens professional communication.