Final answer:
Complementary feeding is the term used for introducing foods to a baby's diet around six months of age, when significant developmental milestones such as teething and improved motor skills occur.
Step-by-step explanation:
Introducing foods to a baby's diet at about six months of age is called complementary feeding. At this stage, the infant's development includes improved motor skills, such as the ability to pick up objects, and vision almost as sharp as an adult's. Additionally, their deciduous teeth usually start to come in, and they show increased interaction with their environment, making this a suitable time to introduce solid foods alongside breast milk or formula feeding.