DCE is the Distributed Computing Environment, from the Open 
Software Foundation. (It is called "the DCE" by sticklers 
for grammatical consistency.)

DCE consists of multiple components which have been 
integrated to work closely together.  They are the Remote 
Procedure Call (RPC), the Cell and Global Directory 
Services (CDS and GDS), the Security Service, DCE
Threads, Distributed Time Service (DTS),and Distributed 
File Service (DFS).  The Threads, RPC, CDS, Security, and 
DTS components are commonly referred to as the "secure 
core" and are the required components of any DCE 
installation.  DFS is an optional component.

DCE is called "middleware" or "enabling technology."  It is 
not intended to exist alone, but instead should be 
integrated or bundled into a vendor's operating system 
offering.  DCE's security and distributed filesystem, for 
example, can completely replace their current, non-network, 
analogs.