• noun:   strengthening the concentration (as of a solute in a mixture) by removing extraneous material
• noun:   bringing together military forces
• noun:   the strength of a solution; number of molecules of a substance in a given volume (expressed as moles/cubic meter)
• noun:   the spatial property of being crowded together
• noun:   complete attention; intense mental effort
• noun:   increase in density
• noun:   great and constant diligence and attention

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