 In a math class, you may have learned about parallel lines. Parallel lines are equally distant, side by side, and aligned. In a literature or history class, you may have heard the term parallel when comparing similar situations or people. In that context, parallel means similar or analogous, as in, her leadership style parallels the prime ministers. In other words, their leadership styles are aligned. When we talk about parallelism in writing and grammar, we also mean alignment. This time in the syntax of a sentence. Parallel structure means that phrases that have similar weight should also have the same grammatical structure. In other words, if the phrases are being used similarly in your sentence, then they should have the same grammatical form. Sentences that lack parallel structure have what English teachers call faulty parallelism, and they can be confusing or awkward. Here's an example. She likes hiking, dancing, and to swim. How would you correct the parallelism in this sentence to help it flow better? There are two ways to pull the phrases into alignment. You can either write, she likes hiking, dancing, and swimming, or she likes to hike, dance, and swim. Both are parallel. Using parallel sentence structure can give your writing balance and rhythm to help deliver your meaning clearly. Faulty parallelism, on the other hand, can be hard for readers to understand. Parallelism comes up a lot in technical and business writing, because faulty parallelism is especially noticeable in bulleted lists. Ideally, all items on a list should start with the same kind of word to be parallel, whether it's on a slide presentation, in a report, or on a resume. Parallel structure helps the reader to see connections more clearly, and in a resume, it helps a hiring manager to take in your accomplishments at a glance. Here's an example of faulty parallelism that you might see on a resume. Balanced nightly till, managing inventory, customer satisfaction. You can see how this is awkward and a little confusing. How would you revise it? In this case, if the job was in the past, then all the items should start with a past tense verb. Balanced nightly till, managed inventory, insured customer satisfaction. So far, we've focused on lists as a place to check for parallel structure. But any phrase that presents two or more items as equally important should also be parallel. This includes either or and neither nor phrases, among others. For example, you know that people either love it or they're hating it sounds awkward. People either love it or hate it is much smoother. Bringing the two halves of the sentence into alignment improves the flow of the sentence and makes it easier to understand. Parallel structure allows your readers to focus on what your words mean rather than how they're structured.