Homelessness is perceived and addressed differently according to country. The European Typology of Homelessness and Housing Exclusion (ETHOS) was developed as a means of improving understanding and measurement of homelessness in Europe, and to provide a common "language" for transnational exchanges on homelessness. The ETHOS approach confirms that homelessness is a process (rather than a static phenomenon) that affects many vulnerable households at different points in their lives.
The typology was launched in 2005 and is used for different purposes: as a framework for debate, for data collection purposes, for policy purposes, monitoring purposes, and in the media. This typology is an open exercise which makes abstraction of existing legal definitions in the EU member states. It exists in 25 language versions, the translations being provided mainly by volunteer translators.