n. A quality of design that takes possible future advances into consideration and attempts to accommodate them
the GNU version of the Collaborative International Dictionary of English
n. The quality of being extensible; the capacity of being extended.
The Century Dictionary and Cyclopedia
n. The quality of being extensible: as, the extensibility of a fiber or of a plate of metal.
Word Usage
"Coflight is also the first FDP to enjoy an open architecture funded over Standard and Open Source middleware technologies to guarantee the long-term extensibility, scalability and availability of supply."