humma // excl. A filler word used on various `chat'
and `talk' programs when you had nothing to say but felt that it
was important to say something. The word apparently originated (at
least with this definition) on the MECC Timeshare System (MTS, a
now-defunct educational time-sharing system running in Minnesota
during the 1970s and the early 1980s) but was later sighted on
early UNIX systems. Compare the U.K's {wibble}.