extrados /ek-strāˈdos/ (architecture)

1. The convex surface of an arch
2. The external curve of the keystone of an arch

• oak tree
• oak trees
• oakum
• oakums
• oak wilt
• oak-wood
• oak-woods
• oaky
• O and M
• OAP
• OAPEC
• oar
• oarage
• oarages
• oared
• oar fish
• oar fishes
• oar-footed
• oarier
• oariest
• oaring
• oar-lap
• oar-laps
• oarless
• oarlock