  Nowadays, according to the observational evidences the curvature parameter of
the universe is neglected and spatially flat FLRW model is on the top of
interest for cosmologists. However, due to some discrepancies between
$\Lambda$-CDM model anticipations and observations, one may think out the
curvature parameter as the solution even though it may be very small. So, in
this article we investigate the eras in which the curvature influence was or is
more significant. In addition, a geometrical interpretation of Hubble parameter
is dedicated. We find that the Hubble parameter is more appropriate to be
defined as the mean curvature of the spatial section of the universe because
the concept of the scale factor in a non-homogeneous universe is not precisely
clear.
