Abstract
We bridge between submanifold theory and contact geometry. We give a
geometric meaning of some fundamental notions such as Sasakian, nearly Sasakian, Kcontact
from the viewpoint of the result in [3] (Theorem 1). Moreover, motivated by
the notion of totally η-umbilic hypersurfaces in a nonflat complex space form, we give a
new notion in contact geometry (Theorem 2).