GNU Collaborative International Dictionary of English

Found one definition

1.       
   Groundling, n. [Ground + -ling.]
   1. (Zool.) A fish that keeps at the bottom of the water, as the loach.
   
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   2. A spectator in the pit of a theater, which formerly was on the ground, and without floor or benches.
   
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   No comic buffoon to make the groundlings laugh. Coleridge.
   
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