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What is the Meaning of “On a side note”?

What is the Meaning of “On a side note”?

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Whenever you are talking to someone, you always want to tie everything you say together.

It makes it easier for the listener to follow you.
This is why you may find yourself using words like “however,” “so,” and “because.”
Each one of these words hints at the relationship between what you are about to say and what you have already said.
You also want a way to prioritize the information you are giving someone.
After all, somethings may be more important or more relevant than others. This is why you may use words and expressions like “incidentally,” “by the way,” and “on a side note.”

With that said, let’s take a closer look at “on a side note.”

What is the Meaning of "on a side note"?


What is the meaning of “on a side note”?

Simply put, “on a side note” is another expression for “parenthetically” or “incidentally.” It’s basically another way of announcing that what you’re about to say may be less important or unrelated to what came before it.


How to use the expression “on a side note?

A simple example is:

“We need to move early tomorrow if we want to make our flight. On a side note, don’t forget to get chewing gum for the flight. You know how the air pressure makes you uncomfortable.”

In the above example, the main information is the need to move early to catch the flight.

Less importantly, the speaker also points out that the listener would do well to bring gum with them.

So, as you can see, “on a side note” usually comes at the beginning of a sentence.

It is a prepositional phrase that acts as an adverbial clause, and it modifies the independent clause following it.
Linguaholic Pull Quote: Meaning of "on a side note"

Where does the expression “on a side note” come from?

When you are reading a book, especially an academic one, you will find some authors will write notes beneath the page or at the end of a chapter.

These notes may pertain to the main text, yet they weren’t important enough to include within the main body.

If anything, the author might have felt that placing these notes within the main text would have broken the flow or logic of the text, explaining why they opted to place these notes separately.

Alternatively, you might choose to scribble down a few notes of your own while reading, and you will probably write these notes on the margins of the book.

And, this is where the term “side note” comes from.

These are the notes that are written in the side margins and tend to be smaller than the main text.

Yet, for the careful readers among you, there should still be something missing? If a side note is that little scribble tucked away in a margin, how can something be “on” it?

Well, you see, there are two meanings for the preposition “on.”

For starters, you have the more literal, physical sense, the meaning that something is on top of something else.

So, you can say, “the cup is on the table.”

Here, “on the table is a prepositional phrase that acts as an adjective clause and is the object of the verb “is.”

Alternatively, “on” can have another meaning. It can mean “regarding.”

For instance, when the French Philosopher Jean-Jacques Rousseau wrote an essay called “Discourse on Inequality,” he was writing an essay about or regarding inequality.

It is in this latter sense that we use the preposition “on” here. When we say “on a side note,” we are actually saying, “regarding a side note.”

This is why this expression usually comes at the beginning of a sentence. It’s sort of like saying, “switching topics,” which is a participial phrase that acts as an adverbial clause.

“Switching topics” is sort of an announcement that has to come at the beginning of a sentence because it affects everything that comes after it. You can’t say, “I’ll finish the presentation.

What should we do about the reservations, switching topics?”

It just sounds weird. You have to say, “I’ll finish the presentation. Switching topics, what should we do about the reservations?”

The same exact thing applies to “on a side note.” If you were to say, “I’ll finish the presentation. I’ll also take care of the reservations on a side note,” the sentence would sound strange and make little sense.

Instead, you should say, “I’ll finish the presentation. On a side note, I’ll also take care of the reservations.”


How has “on a side note” been used historically?

Google has a very interesting function. The search engine behemoth will scour its database of books, looking for certain words.

This can give you important information, such as when a certain word or expression became popular or when a certain term gained wide-spread acceptance.

With this in mind, we can look at Google to find out how “on a side note” has been used over time.

Surprisingly, according to the search engine, this term has gained popularity fairly recently.

In fact, the first usage of “on a side note” can be traced to the late 1980s or early 1990s.

Since then, the term has gained popularity steadily over time, and by 2009, it was used half as much as writers used the expression “switching topics.”


Are there other uses for “on a side note”?

There is another usage for “on a side note,” but this one is a bit specific and may not come around too often.

Simply put, you can use “on a side note” to modify certain verbs.

For example, you can say, “my boss kept commenting on a side note, forgetting the bigger issue at hand.”

Here, what you are trying to say is that your boss kept commenting on a marginal issue rather than focusing on something more important.

As you’ll notice in the above example, “on a side note” modifies the verb “commenting.”

It’s similar to you saying, “he kept commenting about the state of affairs.”

“On a side note” in the earlier example plays the same exact role played by “about the state of affairs” here.

However, in this context, using “on a side note” might be too confusing for the listener. Ergo, you are better off just saying “on a marginal issue” instead.


”On a side note”’s older brother

Even though “on a side note” has been used in literature fairly recently, it does have an older brother that has been around since the early 1860s. I’m talking about the expression “as a side note.”

“As a side note” is constructed by swapping “on” with “as.” Not only is it the older expression of the two, but it is also the more popular one.

According to Google, by 2009, “as a side note” was almost used five times as much as “on a side note.”

Despite these apparent differences in cultural usage, many consider both expressions the same and interchangeable.

In other words, they argue that you can use either expression in a given context, and the meaning wouldn’t be altered all that much.

However, this view isn’t entirely accurate.

You see, there is a slight difference between both expressions, and this is due to the fact that “as” can be a little more nuanced than “on” in this context.

We’ve already seen that “on a side note” comes at the beginning of a sentence because it is an adverbial clause that modifies the sentence following it.

And, when “as a side note” is serving the same function, modifying the independent clause, it also comes at the beginning of a sentence.

However, “as a side note” can also modify specific verbs instead of the entire sentence.

For instance, when you say, “He made that comment as a side note,” “as a side note” acts as an adverbial clause that modifies the verb “made.”

Similarly, when you say, “that comment acted as a side note,” “as a side note” is modifying the verb “acted” drawing our attention to how the comment behaved.

As you can see, the secondary usage of “on a side note” is different than the secondary usage of “as a side note.”

The former describes actions done in relation to a marginal issue, such as being commented on when you “keep commenting on a side note” or being focused on when you “keep focusing on a side note.”

The latter expression describes actions that behave in a marginal fashion, such as when a comment is made “as a side note.”

This difference might seem minute, but the devil is always in the details.