To leach means to slowly drain or draw something out, usually as liquid filters through a material. When rainwater leaches through soil, it pulls minerals and nutrients down with it, carrying them deeper into the ground or washing them away entirely. A gardener might worry about heavy rains leaching important nutrients from the soil, leaving plants without the food they need to grow strong.

The word often describes something being removed gradually and unintentionally. Coffee makers work by leaching flavor and caffeine from ground coffee beans as hot water passes through them. Old batteries buried in a landfill can leach harmful chemicals into the groundwater below. A cook might leach excess salt from vegetables by soaking them in fresh water.

Think of leaching as a slow drain or seep, where liquid acts like a thief, carrying away dissolved substances as it moves through something. The process happens steadily over time rather than all at once. Scientists worry about fertilizers leaching from farm fields into rivers. The key idea: something valuable or important slowly dissolves and disappears, carried off by moving liquid.