Binding affinity refers to the strength of the interaction between a molecule, such as a drug, and its target, like a protein or receptor. It is a crucial concept in fields like biochemistry and pharmacology, as it helps determine how effectively a drug can bind to its target and elicit a biological response. Higher binding affinity indicates a stronger interaction, which often leads to more effective therapeutic outcomes. In scientific terms, binding affinity is often measured using techniques like surface plasmon resonance or isothermal titration calorimetry. The results are typically expressed as a dissociation constant (Kd), where a lower Kd value signifies a higher affinity. Understanding binding affinity is essential for drug design and development, as it influences dosage and efficacy.