The Zisman plot the graphical method of the Zisman theory or the Zisman method for characterizing the wettability of a solid surface [https://www.kruss-scientific.com/services/education-theory/glossary/method-according-to-zisman/], named for the American chemist and geophysicist, William Albert Zisman (1905–1986).  It is a prominent Sessile drop technique used for characterizing liquid-surface interactions based on the contact angle of a single drop of liquid sitting on the solid surface.