The use of a word to modify or govern two or more words when it is appropriate to only one of them or is appropriate to each but in a different way, as in to wage war and peace or On his fishing trip, he caught three trout and a cold.
Of course, the zeugma is not an eighteenth-century invention, but it was not handled before then with such neatness and consciousness, and had not the same air of being the normal process of thought.
-- William Empson, Seven Types of Ambiguity
If we take "We will be proud of course the air will be" as a strong syntactical unit, a complete sentence, the parallelism of "we will be" and "the air will be" draws both these auxiliary phrases toward the yoke (or zeugma, in rhetorical parlance) of the main verb phrase.
-- Cary Nelson, Ed Folsom, W. S. Merwin: Essays on the Poetry
Zeugma stems from the Greek word of the same spelling which meant "a yoking."