The number and the evolution of its concept have long been subjects of interesting discussions among philosophers, logicians, mathematicians, and literary scholars. In human history, the origins of numbers arose from specific practical needs. “One” is one of the simplest yet most fundamental concepts in mathematics. It emerges in the earliest experiences of counting, but throughout the development of human thought, it has acquired meanings and functions far beyond simple counting. Archaeological evidence indicates that numbers emerged before writing. The earliest records of counting are found not in words, but in notches carved on on wood, stone, or bone. As societies evolved and more complex needs emerged, “one” gradually developed from a simple counting mark into various forms and functions, including the cardinal and ordinal number, the unit, oneness, one-to-one correspondence, and, in more recent periods, the identity element and a fundamental component of the binary system. Alongside these developments, “one” has acquired diverse meanings and connotations in language, philosophy, spiritual traditions, and ancient thought. Using a descriptive-analytical method and a genealogical approach, this paper examines the historical and conceptual transformation of “one,” from the earliest forms of counting to some of its contemporary applications, bringing historical, philosophical, linguistic, cultural, and technological perspectives into dialogue. The findings show that, despite its apparent simplicity, “one” is neither a single-meaning nor a single-function concept; rather, it has developed diverse functions within historical and epistemic contexts and acquired different meanings and implications in areas such as language, culture, mathematics education, and technology. Accordingly, the genealogy of “one” can be regarded as an instance of the transformation of a mathematical concept from concrete experiences and practical applications toward more abstract forms-a transformation that lies at the intersection of the history of mathematics, philosophy, language, culture, and technology.