Wiktionary
n. 1 A reduction in emphasis. 2 (context lang=en telecommunications) A signal distortion, carried out at a receiver, in order to undo the effects of pre-emphasis at the transmitter. 3 (context lang=en telecommunications) A reduction of the level of all bits except the first one after a transition.
Usage examples of "de-emphasis".
The result had been a radical de-emphasis of what the old-school types called "military polish"
The result had been a radical de-emphasis of what the old-school types called "military polish" and certain others called "Mickey Mouse" without knowing the term's origin.
In addition, the idea of an uncomplicated style was very much in the air back then -- clarity, shorter sentences, strong verbs, a de-emphasis of adverbs and adjectives, that sort of thing.