Demarcation involves setting boundaries or limits, essentially distinguishing or separating areas. In the field of medicine, it is primarily used to identify and outline boundaries. For instance, when discussing damaged tissue, surface demarcation defines the line between healthy and necrotic (dead) tissue.The term "demarcation" originates from the Italian verb "marcare," meaning "to mark." This evolved into the Spanish verb "marcar," and later "demarcar," which means "to establish a boundary." In 1493, the Spanish noun "demarcacion" was coined to label the newly established meridian separating the Spanish Indies from the Portuguese Indies. By around 1730, English speakers began referring to this boundary as the "line of demarcation," a term that eventually extended to other types of boundaries.