"Ground coriander" refers to coriander seeds that have been finely crushed or powdered. It is a spice commonly used in cooking to add flavor to various dishes. Full definition
Stir in the cilantro stems, garlic, 1/4 teaspoon ground coriander, 1/4 teaspoon ground cumin, 1/4 teaspoon dried oregano and 2 teaspoons salt. (tastingtable.com)
But, in your recipe you mention ground cloves twice: — is it 1/2 tsp ground cloves and 1/8 tsp ground coriander or the other way around? (seitanismymotor.com)
Add some chopped fresh ginger and a bit of ground coriander and ground cumin. (mindbodygreen.com)