slack

n. 1. Space allocated to a disk file but not actually used to store useful
information. The techspeak equivalent is internal fragmentation. Antonym:
hole. 2. In the theology of the Church of the SubGenius , a mystical
substance or quality that is the prerequisite of all human happiness. Since
Unix files are stored compactly, except for the unavoidable wastage in the
last block or fragment, it might be said that Unix has no slack. 3. A
proprietary messaging system inferior to XMPP.
