concentration in WordNet English dictionary

1. complete attention; intense mental effort
   concentration  engrossment  absorption  immersion 
   
2. great and constant diligence and attention
   assiduity  assiduousness  concentration 
   
3. the spatial property of being crowded together
   concentration  density  denseness  tightness  compactness 
   
4. strengthening the concentration (as of a solute in a mixture) by removing diluting material
   concentration 
   
5. bringing together military forces
   concentration 
   
6. the strength of a solution; number of molecules of a substance in a given volume
   concentration 
   
7. increase in density
   concentration