[pri-kur-ser, pree-kur-] 
| 1. | a person or thing that precedes, as in a job, a method, etc.; predecessor. |
| 2. | a person, animal, or thing that goes before and indicates the approach of someone or something else; harbinger: The first robin is a precursor of spring. |
| 3. | Chemistry, Biochemistry. a chemical that is transformed into another compound, as in the course of a chemical reaction, and therefore precedes that compound in the synthetic pathway: Cholesterol is a precursor of testosterone. |
| 4. | Biology. a cell or tissue that gives rise to a variant, specialized, or more mature form. |
| pre·cur·sor (prĭ-kûr'sər, prē'kûr'sər) n.
[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 Indo-European roots.] |
precursor pre·cur·sor (prĭ-kûr'sər, prē'kûr'sər)
n.
One that precedes and indicates something to come.
One that precedes another; a forerunner or predecessor.
A biochemical substance, such as an intermediate compound in a chain of enzymatic reactions, that gives rise to a more stable or definitive product.
sər