Source : Webster's Revised Unabridged Dictionary (1913)

Seggar \Seg"gar\, n. [Prov. E. saggard a seggar, seggard a sort
   of riding surtout, contr. fr. safeguard.]
   A case or holder made of fire clay, in which fine pottery is
   inclosed while baking in the kin. [Written also {saggar},
   {sagger}, and {segger}.] --Ure.