hemidome

\\ˈ ̷ ̷ ̷ ̷+ˌdōm\ noun

Etymology: International Scientific Vocabulary hemi- (I) + dome

1. : a pinacoid parallel to the orthoaxis and cutting the vertical axes and clinoaxes in a crystal

2. : a dome that has only two like faces (as an orthodome of a monoclinic crystal)