A dictionary for UNIX systems

['Olafur Thorsteinsson]

I posted this to the places I thought would be most likely to be able to
give me info (of course, where else would I put this).  I hope I found at
least one good spot.

Is there a good on-line dictionary available for UNIX systems out there?
If so, where can I find out more about it?
Are there many, and then which one can you recommend?

Many thanks for your time and responses.

	 'Olafur Thorsteinsson
	 thors at umn-cs.cs.umn.edu