[voo-swahr] 
| any of the pieces, in the shape of a truncated wedge, that form an arch or vault. |
| vous·soir (vōō-swär') n. One of the wedge-shaped stones forming the curved parts of an arch or vaulted ceiling. [French, from Old French vossoir, from Vulgar Latin *volsōrium, from *volsus, past participle of Latin volvere, to turn, roll; see wel-2 in Indo-European roots.] |