similar to "damn" in the form "day-UM". an extremely useful, generally non-offensive and throughly multi-purpose exclamation.
Person 1: Dude, I just won the f***ing lottery!!!
Person 2: Helladank!
*highfives all around*

or

Person 1: Dude, my uncle died this weekend.
Person 2: Well, helladank.
*sad, contemplative faces*
by NerakanDrac November 20, 2009
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A term used by Nathan Owens on DesandNate. It really has no meaning.
by crazedmuffin July 4, 2010
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