Development is the act of improving by expanding, enlarging, or refining. The merging of two university departments might lead to the development of a new curriculum.
There are many other definitions for this noun, too. Real estate development is the conversion of land or property to a specific use, like housing or retail space. To grow up, we pass through many stages of development, from infancy to old age. Breaking news is often followed by developments, that is, recent events or information that's relevant to the story.