# precursor

/pɹiˈkɝsɝ/ (US) · /pɹɪkˈɜːsɐ/ (UK)

Source: https://englishreference.com/word/precursor
Updated: 2026-08-08

## Senses

### 1. a forerunner or predecessor

noun · CEFR C1 · Academic

something that happened or existed before another thing, especially if it influenced the later thing.

For teachers: a person or thing that precedes another, often serving as a prototype or an indicator of future developments.

- The small local protest was a precursor to the national movement that followed.
- Historians often view the early 19th-century steam carriage as a direct precursor to the modern automobile, despite its limited commercial success.

Usage: Often followed by the preposition 'to'.

### 2. chemical starting material

noun · CEFR C1 · Technical

a chemical substance that is used to make another substance during a reaction.

For teachers: a compound that participates in a chemical reaction that produces another compound.

- The lab needs a specific precursor to create the new medicine.
- The synthesis of the polymer requires a highly purified precursor to ensure the final product maintains its structural integrity.

Usage: Commonly used in biochemistry and industrial chemistry contexts.

## Examples

- 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.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.