1. Power to be effective; the quality of being able to bring about an effect
   - effectivity, effectualness, effectuality 
2. Capacity to produce strong physiological or chemical effects
   - potency, strength

Derived forms: effectivenesses

See also: effective, impotent, ineffective, ineffectual, potent, stiff, strong, uneffective

Type of: power, powerfulness

Antonym: ineffectiveness

Encyclopedia: Effectiveness

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