What are solid foods?
Keeping this in consideration, is Rice a solid food?
There are reasons why rice cereal is so popular: it's easy to digest, doesn't trigger an allergic reaction as the gluten in wheat can, and is well tolerated by babies who are transitioning from breast milk or formula to solid food. In an appropriate quantity, it's still a food you can include in your baby's diet.
Herein, what is a non solid food?
Fruit juices, including nectars and juices with pulp. Butter, margarine, oil, cream, custard, and pudding. Plain ice cream, frozen yogurt, and sherbet. Fruit ices and popsicles. Soup broth (bouillon, consommé, and strained cream soups, but no solids)
Other foods, such as eggs, fish, and meats may also be given once a baby is comfortable eating other solids. Eggs are an excellent source of protein and are full of nutrients, including Vitamin D, calcium, choline and many more that will complement a baby's diet. One good article on starting solid foods is linked here.