A zeugma is an interesting device that can cause confusion in sentences, while also adding some flavor. Let's take a famous example from Star Trek: The Next Generation: "You are free to execute your laws, and your citizens, as you see fit." In this sentence, the word "execute" applies to both laws and citizens, and as a result, has a shocking effect.
Therefore, a zeugma is a figure of speech where a word applies to multiple parts of the sentence. In the above example, it has a dramatic effect. However, sometimes the attempted use of a zeugma can be confusing.
The zeugma is sometimes utilized to create drama, add emotion or produce some sort of shock value. While there can still be an underlying sense of confusion, generally an zeugma is used purposely as shown in these examples:
All of these examples serve a particular purpose. For example, with the "His boat and his dreams sank" example, the zeugma creates a more powerful sentence. The emotions of a person losing a lifelong dream as a sailor are more pronounced in this sentence than in a construction such as this: The man's boat sank. He realized his dreams were slipping away.
Sometimes, when people try to use a zeugma in their writing, they will find themselves bordering on dangling modifier issues. It's important to use zeugma in the clearest ways possible and to always have a purpose for doing so.
"Sitting by the fence, the dog growled at the cat" is an example of when zeugma goes wrong. If you wrote that sentence, you may think that you are making it clear that both the dog and the cat are sitting by the fence. However, you have actually created a dangling modifier. Due to the placement of the word "sitting," it is unclear as to whether the dog, the cat or both of the animals are sitting near the fence.
Another example of such a construction is as follows: "Walking by the tree, the child waved to her friend." Again, who is walking by the tree? One child or both of the children? These two attempts at zeugma can be easily corrected, although they will not necessarily produce zeugmas. "While the dog and the cat were sitting by the fence, they growled at each other" and "When the two girls walked by the tree, they waved to each other" are both suitable alternatives.