Writers from Homer to O. Henry have used it. Critics from Servius to Bömer have commented on it. Students of rhetoric from Quintilian to Laussberg have analysed it. Yet there is very little agreement about what zeugma is and what it does. Some editors note its existence and leave it at that. Others distinguish (sometimes passionately) between zeugma and syllepsis, zeugma and equivoque, zeugma and attelage, zeugma and plokē, zeugma and amphibole. Therefore I shall do well to clarify at the start my own use of the term.
It is probably best to begin by distinguishing between a group of figures (most commonly called zeugma or syllepsis) which link several notions into one, and another group (hendiadys and related figures) which expand one concept by expressing it in two ways or from two points of view. Zeugma implies yoking (zeugnumi), two or more elements joined so as to make a team. The yoked words are in some way incongruous — perhaps abstract linked with concrete, animate with inanimate, or physical with mental — and the resulting team is, accordingly, both surprising and noteworthy, rather as if a horse were yoked with an ox.