The IRS is the U.S. government agency responsible for tax collection and tax law enforcement. Contains downloadable forms, instructions, and agency publications. It also includes ...
http://www.irs.gov/

adjective . 1. situated or existing in the interior of something; interior. 2. of, pertaining to, or noting the inside or inner part. 3. Pharmacology. oral (def. 4).
http://dictionary.reference.com/browse/internal

Internal may refer to: Internal Revenue Service; Internal medicine; Internal set theory; Internal Conflict
http://en.wikipedia.org/wiki/Internal

The internal keyword is an access modifier for types and type members. Internal types or members are accessible only within files in the same assembly, as in this example:
http://msdn.microsoft.com/en-us/library/7c5ka91b.aspx

Archives of Internal Medicine, a bi-monthly professional medical journal published by the American Medical Association, publishes original peer-reviewed research articles on ...
http://archinte.ama-assn.org/