Words that seem interchangeable … but aren’t

Posted on January 26, 2026

One of the dilemmas that writers face is trying to use a variety of words to mean the same thing, so the reader won’t get bored and skip ahead. Synonyms can be valuable, but some of the words or phrases you might like to use are actually not synonyms. Let’s look at a few of those.

Because, since, as

Clauses that begin with because, since or as can either start a sentence or finish a sentence. But people use these three words as if they’re interchangeable, and usually, they’re not.

Because focuses on the reason, the cause behind a certain effect, if you will. We use because when we’re giving the reason for something. For example:

  • I’m rolling my eyes because the light rail transit system is still not finished.
  • Because I won’t work overtime this week, my manager is unhappy.
  • We’ll come to visit on Sunday because Andrew has to work on Saturday.

Since refers to a time frame. For example:

  • They haven’t seen him since last week.
  • We’ve been married since 2019.
  • Since it snowed last night, I have not been outside.

Sometimes, since expresses a mild degree of causality. If we use since in a sentence expressing cause and effect, the reader should already know the reason for the action. For example, “Since the Maple Leafs lost in the quarter-finals, Canadian fans have nothing to cheer about.”

As applies to timing, when two things are true at the same time. You can test this by substituting while for as. If the sentence reads smoothly, you’ve used the word correctly. For example:

  • The director general paused as the minister walked into the room.
  • We enjoyed sticky toffee pudding as we watched the movie.

If you use as instead of because, readers may find themselves stumbling over the sentence, needing to reread it to clearly understand your meaning. Worse, they might not understand exactly what you’re telling them, regardless of the number of times they reread the text.

What does all this mean for writers? Increase the clarity of your writing: if you’re giving a reason, use because; if you’re identifying a time frame, use since; if you’re expressing timing, use as (or while).

And, as well as

These two aren’t interchangeable. Ever.

And joins two items of equal importance. They can be single words, phrases or clauses. The key is that each is as important as the other, so the order doesn’t matter. This applies whether the items are similar or different. For example:

  • I like to watch movies, read books and visit friends.
  • Plain language techniques are the same for English and for French.
  • Asking questions and listening closely are two valued qualities in meetings.

As well as joins two items that are not equally important; one word, phrase or clause is more important than the other, and it comes first in the sentence. The less important item follows. As well as is also more commonly used for similar items than for different items. For example:

  • I like to play board games as well as watch movies.
    [Message: board games are more important than movies]
  • He packed three shirts and coordinating slacks as well as a sports jacket.
    [Message: shirts and slacks are more important than jacket]
  • They welcomed their families as well as the neighbours.
    [Message: families are more important than neighbours]

Furthermore, depending on the sentence structure, subject-verb agreement can become an issue when using as well as. Test the subject-verb agreement by removing the as well as phrase. For example:

  • The chimpanzee as well as the gorilla is a primate.
    [The chimpanzee is a primate. Correct.]
  • The bonobo and the orangutan, as well as the gorilla, are primates.
    [The bonobo and the orangutan are both primates. Correct.]

What about those commas? A pair of commas indicates that the words in between can be eliminated without losing meaning. I have not seen commas used in sentences where as well as identifies a secondary item. However, I inserted them in the second example immediately above because I believe that they increase clarity for the reader. I very rarely see a sentence where a phrase with multiple elements is used to express the more important item, perhaps for a reason.

What does this mean for your writing? Decide if the items you’re writing about are equally important or not. If equal, use and; if unequal, use as well as.

Less, fewer

The use of less and fewer relates to count and non-count nouns. If you can count the items, use fewer. If you can’t count the items, use less. For example:

  • It seems like fewer cars are on the roads on Mondays than on other weekdays.
  • Canada shipped less grain in 2020 than in 2024.
  • Canada shipped fewer tonnes of grain in 2020 than in 2024.

Cars and tonnes are countable, but grain is not. Other non-count nouns include sports or games, fields of study, languages, and liquids.

You might wonder about using less or fewer with percentages. The basic rule remains the same: use fewer with count nouns (for example, people, books, contracts, days) and use less with non-count nouns (for example, equipment, advice, silver, jewelry, baggage). For example:

  • The department required 23% fewer contracts than five years ago.
  • Results indicate that 38% fewer people agreed with that stance than when this survey was conducted 10 years ago.
  • The annual report stated that the company mined 18% less gold than last year.
  • The project took 15% less time than expected.

What does this mean for your writing? Use fewer with items you can count, and use less with items you can’t count.

In conclusion, appropriate word choice always increases the clarity of your writing. Choose words that help your readers understand exactly what you’re saying without a need to stop and ponder the meaning behind them.

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The opinions expressed in posts and comments published on the Our Languages blog are solely those of the authors and commenters and do not necessarily reflect the views of the Language Portal of Canada.

Get to know Elva Keip

Elva Keip

Elva Keip works as a consultant and provides both training and writing services to clients. Most of her courses focus on writing well. Regardless of the topic, every course features a brief section on using plain language to avoid confusion and misunderstanding. She loves writing documents and supporting other people as they enhance their writing skills.

 

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