As an adjective midling
is .
As a noun midline is
(anatomy|medicine) the medial line (or plane) of the body, which divides the body into halves that are mirror-images of each other.
midline
English
Noun
(
en noun)
(anatomy, medicine) The medial line (or plane) of the body, which divides the body into halves that are mirror-images of each other.
(typography) The level of the top of the x-height of a typeface.