A soil amendment (crushed limestone, calcium carbonate) that raises soil pH by neutralizing acidity, used to adjust acidic soils toward neutral.
Lime (agricultural limestone or hydrated lime) raises soil pH. Acidic soil + lime = more neutral soil. It works slowly (takes months); apply in fall for spring effect. Too much lime causes over-alkaline soil blocking nutrient uptake; test soil first, apply per test recommendations.
Lime is essential for acidic soil correction. Understanding when to use lime (and when not to) prevents over-liming.