Terroir (teh-RWAHR) is the idea that place shapes flavor — the same grape variety grown on different hillsides makes distinctly different wines because of soil, climate, aspect, and vintner tradition. The concept originated in French wine and has spread to cheese (hence "terroir-driven cheese"), coffee, olive oil, and even tomatoes and honey.
For local food, terroir is the theoretical underpinning of why buying local matters beyond freshness: a tomato grown on a specific farm in a specific region tastes like that place in a way a commodity tomato doesn't.