Complex is an adjective meaning consisting of many different and connected parts.
In psychology, a complex refers to a group of emotionally significant ideas that are completely or partly repressed.
The term "complex" also refers to:
1. A building or group of buildings designed for a particular purpose
2. In chemistry, a structure consisting of a central atom bonded to surrounding atoms
3. In mathematics, a number of the form a + bi, where a and b are real numbers