pre·cur·sor (prĭ-kûrsər, prēkûr′sər)
1. One that precedes and indicates, suggests, or announces someone or something to come: Colonial opposition to unfair taxation by the British was a precursor of the Revolution.
2. One that precedes another; a forerunner or predecessor: The new principal's precursor was an eminent educator.
3. A biochemical substance, such as an intermediate compound in a chain of enzymatic reactions, from which a more stable or definitive product is formed: a precursor of insulin.
[Middle English precursoure, from Old French precurseur, from Latin praecursor, from praecursus, past participle of praecurrere, to run before : prae-, pre- + currere, to run; see kers- in the Appendix of Indo-European roots.]
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Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.