Cessor \Ces"sor\, n. [From {Cess}, v. i. Cf. {Cesser}.] (Law) One who neglects, for two years, to perform the service by which he holds lands, so that he incurs the danger of the writ of cessavit. See {Cessavit}. --Cowell. Cessor \Ces"sor\, n. [From {Cess}, v. t.] An assessor. [Obs.]