In C programming, a structure is a user-defined data type that allows you to group together different types of variables under a single name. Each variable within the structure is called a member or field. Structures are useful for organizing and representing complex data in a more structured way. The general syntax for defining a structure in C is as follows:

struct structure_name {

    data_type member1;

    data_type member2;

    // ... additional members

};