1. Capable of being extended or protruded: an extensible tongue; extensible tables.
2. Computer Science. Of or relating to a programming language or a system that can be modified by changing or adding features.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.