The word "cognitive" refers to the thought process toward awareness or knowledge. Needs a better explanation. Also see related word: reCOGNITION- having something come back into your awareness/memory.
Cognitive development is a field of study in neuroscience and psychology focusing on a child's development in terms of information processing, conceptual resources, perceptual skill, and other topics in cognitive psychology. A large portion of research has gone into understanding how a child conceptualizes the world. Jean Piaget was a major force in the founding of this field, forming his "theory of cognitive development". Many of his claims have since fallen out of favor.
A major topic in cognitive development is nativism versus empiricism. Another is the question of convergance or homology with animals when humans have similar cognition. These two debates are present in nearly every smaller part of the field.