Far-reaching means having effects or influence that extend over a large area, affect many people, or continue for a long time. When something is far-reaching, its impact spreads widely beyond its starting point.

The invention of the printing press had far-reaching consequences: it made books cheaper and changed education, religion, politics, and science across entire continents for centuries. When a school principal makes a far-reaching decision to change how grades work, it affects every student, teacher, and family in the school, spreading well beyond any single classroom.

Far-reaching can describe physical distance too. A far-reaching trade network might connect merchants across thousands of miles. A tree's far-reaching roots spread deep and wide underground, stabilizing the soil and drawing water from a large area.

The word often appears when people are considering the full impact of a choice or event. A scientist discovering a new medicine can create far-reaching benefits for patients everywhere. A careless decision to pollute a river has far-reaching effects on communities downstream.