At Galois's time, fields were known as "domains of rationality" because they admit all rational operations: addition, subtraction, multiplication, and division (by nonzero elements).

In the 1870s, Dedekind singled out algebraic number fields for special attention and gave them the name Körper. This is the German word for "body," which Dedekind thought appropriate because closure under rational operations makes these domains, in some sense, complete and self-contained. Later, the word Körper became "field" in English, though the influence of Körper lingers in the letter K often used to denote a field in English-language algebra books.