precursor
n. countablen. something that comes before another thing and leads to its development. In science, it is a substance that is used to create a different substance.
n. a person or thing that precedes another of the same kind; a forerunner. In a biochemical context, it refers to a substance from which another is formed.
The small protest was a precursor to the full revolution.
Researchers identified a specific protein in the blood that acts as a precursor to the development of the disease.
While the steam engine was a vital precursor to modern industrialization, its early designs were far less efficient than the models that eventually transformed global transport.
Inherited from Middle English precursour, from Middle French precurseur or its etymon Latin praecursor (“forerunner”). By surface analysis, precurse + -or.
From pre- + cursor.
Often followed by the preposition 'to' when describing a historical or logical forerunner.