From Science Europe Data Glossary
Definition: data archiving is the process of moving data that is no longer actively used to a separate data storage device or system for long-term retention (in a narrow sense). In a wider sense, the term is loosely used to encompass all activities performed by data archives, including data stewardship, data curation, and data management.
Alternative definition: research data archiving is the long-term storage of scientific data and methods.
Explanation: research funding organisations and research institutions increasingly require that research data resulting from their funding is publicly archived, although policies and practices differ considerably. Similarly, scholarly journals have differing policies regarding how much of their data and methods scientists are required to store in data archives, and what is actually archived varies widely between different disciplines. In general, the tradition of science and scholarship has been for publications to contain sufficient information to allow fellow researchers to replicate and therefore test the research. In recent years this approach has become increasingly strained as research in some areas depends on large datasets which cannot easily be replicated independently. Thus data archiving is more important in some fields than others. In a few fields, all (or most) of the data necessary to replicate the work is already available in the journal article. In other fields, a great deal of data is generated and must be archived separately so researchers can verify that the reports accurately reflect the claims.
References: http://searchdatabackup.techtarget.com/definition/data-archiving; http://www.emc.com/corporate/glossary/data-archiving.htm; http://en.wikipedia.org/wiki/Scientific_data_archiving
See also: data archive; data centre; data repository