Integration, in the most general sense, may be any bringing together and uniting of things: the integration of two or more economies, cultures, religions (usually called syncretism), etc.
Integration, in mathematics, a concept of calculus, is the act of finding integrals
Integration clause, in a contract, a term used to declare the contract the final and complete understanding of the parties
In computer science
Digital integration, in computer science, allows data from one device or software to be read or manipulated by another, resulting in ease of use
Enterprise application integration, as the use of software and computer systems to bring together a set of enterprise computer applications
Systems Integration, refers to the discipline of designing systems by means of glueing together otherwise separate parts. Usually associated to the construction of complex systems.