arch1
  
  n.
  - a curved symmetrical structure spanning an opening and supporting the weight of a bridge, roof, or wall. ▸an arch-shaped curve. 
- the inner side of the foot.
v.
 form or cause to form an arch.
Derivative
  
  Etymology
  ME: from OFr. arche, based on L. arcus ‘bow’.
 
  
    
arch2
  
  adj.
 self-consciously playful or teasing.
Derivative
  
  Etymology
  C17: from arch-, by assoc. with the sense ‘rogue’ in combinations such as arch-scoundrel.