From EUROCONTROL ATM Lexicon
a database in which data collected from several operational systems is integrated and stored by subject in such a way that it can be easily analysed, esp. for making informed management decisions.
Oxford English Dictionary (2004)
A data warehouse contains data which is built out of separate internal and/or external data sources where the data is integrated in a consistent manner. The database design of a data warehouse favours data analysis and reporting in order to gain strategic insight and to facilitate decision-making. A data warehouse contains “fact tables” and “dimension tables” which may be arranged as a “star schema” or a “snowflake schema”
ICAO (2009) Doc.9883, Manual on Global Performance of the Air Navigation System