資料來源 : Webster's Revised Unabridged Dictionary (1913)

Lustrum \Lus"trum\, n.; pl. E. {Lustrums}, L. {Lustra}. [L. Cf.
   2d & 3d {Luster}.]
   A lustration or purification, especially the purification of
   the whole Roman people, which was made by the censors once in
   five years. Hence: A period of five years.

資料來源 : WordNet®

lustre
     n 1: a surface coating for ceramics or porcelain [syn: {luster}]
     2: a quality that outshines the usual [syn: {luster}, {brilliancy},
         {splendor}, {splendour}]
     3: the visual property of something that shines with reflected
        light [syn: {shininess}, {sheen}, {luster}]
     [also: {lustra} (pl)]

lustra
     See {lustre}