pyramidal
adjective /ˈpɪrəmɪdl/
  /ˈpɪrəmɪdl/
- having a square or triangular base and sloping sides that meet in a point at the top
- a pyramidal roof/tent
 
 - piled in the shape of a pyramid
- the familiar pyramidal arrangements seen in fruit markets
 
 - (of an organization or system) in which there are fewer people at each level as you get near the top
- a pyramidal authoritarian leadership structure