(märk`bär)n.
a break-through scientific event of granola bars discovered by Mark Twain Henley the third, during the 1990's. The MarkBar™ is a granola bar composed of raw element which can cause adrenaline and increase of testosterone within a matter of minutes. Many people in language arts classes search for these bars to increase their energy. But they are only for emergency purposes.;
slang. something that gives you energy.