Definitions:
the main means of mass communication (broadcasting, publishing, and the internet) regarded collectively

an intermediate layer in the wall of a blood vessel or lymphatic vessel.

an ancient region of asia to the south-west of the caspian sea, corresponding approximately to present-day azerbaijan, north-western iran, and north-eastern iraq. originally inhabited by the medes, the region was conquered in 550 bc by cyrus the great of persia.