Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Semantic matching is a technique used in Computer Science to identify information which is semantically related. Given any two graph-like structures, e.g. classifications, database or XML schemas and ontologies, matching is an operator which identifies those nodes in the two structures which semantically correspond to one another. For example, applied to file systems it can identify that a folder labeled car is semantically equivalent to another folder automobile because they are synonyms in English. This information can be taken from a linguistic resource like WordNet.