Definitions of infusion:

• noun:   the act of infusing or introducing a certain modifying element or quality

  Example: "The team's continued success is attributable to a steady infusion of new talent"

• noun:   (medicine) the passive introduction of a substance (a fluid or drug or electrolyte) into a vein or between tissues (as by gravitational force)
• noun:   the process of extracting certain active properties (as a drug from a plant) by steeping or soaking (usually in water)
• noun:   a solution obtained by steeping or soaking a substance (usually in water)