"newspapers, radio, TV, etc." 1927, perhaps abstracted from mass-media (1923, a technical term in advertising); plural of medium (n.) as "intermediate agency," a sense attested in English from c. 1600. Also see -a (2).
meddling
Mede
Medea
medevac
*medhyo-
media
mediaeval
medial
medially
median
mediant