Definition: The word "prd.i" refers to the first part of a compound, usually with two elements fused together in a chemical reaction. Here's its definition: - Prd.i - The first part of a compound (usually one element) bonded to another element or substances during chemical reactions. - Prd.1 - The second part (element A) of the compound that is bonded to the first part (element B). For example, in a reaction between glucose and water to form glycogen, "Prd.i" refers to the first part (glucose), while "Prd.1" refers to the second part (water).