The Small World of Words project is a large-scale scientific study that aims to build a map of the human lexicon in the major languages of the world and make this information widely available. In contrast to a thesaurus or dictionary, this lexicon provides insight into what words and what part of their meaning are central in the human mind. The results enable psychologists, linguists, neuroscientists and others to test new theories about how the human brain represents and processes language.

The project started in 2003 in the University in Leuven's (Belgium) Experimental Psychology Department and has since built the largest available network of word associations in Dutch (more than 5 million responses) and English (more than 1 million responses). With the help of language researchers all over the world similar projects are now set up in many different languages. Such diversity allows researchers to compare these lexicons across the globe and further study how language and meaning are represented in the mind.

In the latest version of the project, responses by participants are immediately integrated into the lexicon, so people can look up words they contributed to.