As an adjective cylindrical
is shaped like a cylinder.
As a noun fishmouth is
(roofing) a half-cylindrical or half-conical shaped opening or void in a lapped edge or seam, usually caused by wrinkling or shifting of ply sheets during installation.
fishmouth
English
Noun
(
en noun)
(roofing) a half-cylindrical or half-conical shaped opening or void in a lapped edge or seam, usually caused by wrinkling or shifting of ply sheets during installation.