The powdered root of the Zingiber officinale. While it comes from the same plant as the fresh rhizome, ground ginger is a distinct ingredient with a different culinary personality. The drying process removes the volatile oils responsible for the bright, citrusy "zing" of fresh ginger, replacing them with shogaols—compounds that offer a deeper, slower, and warmer heat. It is the nostalgic scent of gingerbread and the warm hum in a spice rub, essential for baking and curries alike.