Mille fiori is an art of ornamented glass, fusing together a variety of pieces of colorful rods. The actual term is Italian, meaning "thousands of flowers."
a mille fiori paperweight
Significance to Stevens[]
Stevens mentions mille fiori in his poem "Winter Bells," saying "He preferred the brightness of bells, / The mille fiori of vestments, / The voice of centuries / On the priestly gramophones" (5-8). Mille fiori is an art style that takes time, skill, and a certain set of conditions (heat, immediacy, delicacy, dexterity, etc.), so this indicates the best of the best. To have "the mille fiori of vestments" means to have colorful, pieced together clothing with utmost craft.