What's the difference between "on a side note" and "by the way"? Is one of them restricted to certain situations while the other is not?


By the way may bring up a new major topic — related to the previous one. You may shift the whole conversation into a new direction, and keep it on that new topic for a while, drilling it thoroughly.

On a side note should be just a small side note — similarly you shift the subject somewhat, but you just drop a small bit of information and you're either back to the previous topic or ending the conversation.

Other than that, you'll see the two in somewhat different contexts. You'll rarely hear someone asking a question "on a side note", while "and by the way, did you...?" style questions are very common. "By the way" is more informal, commonly appearing in day-to-day speech, while "on a side note" would be something to be seen more in more formal contexts.

  • Wow - subsubsets. Pragmatic markers subset reorientation markers subsubsets major and minor! – Edwin Ashworth Feb 7 '14 at 10:04
  • 4
    Adding to this, "on a side note" is not that common to begin with (cf. WS2's answer) — "as a side note" is more common, and "as an aside" is more common still. COCA has 7, 20, and 115 cites, respectively. BNC has 0, 0, and 18. – RegDwigнt Feb 7 '14 at 10:10
  • As an aside, here are the sources of @RegDwigнt's numbers above: corpus.byu.edu/COCA & corpus.byu.edu/bnc for those interested. – flow2k Jul 31 '18 at 18:21

I have never come across 'on a side note'.

I think 'incidentally' is a good word to use for an aside.

During a conversation between two lawyers, let's say about someone's willingness to give evidence in court, one of them might say: 'Did you know, incidentally, that he has a criminal record?'.

Or with a doctor, when discussing feeling unwell, 'I have, incidentally, just returned from a journey up the Amazon in a rowing boat'.

  • books.google.com/ngrams/… – mplungjan Feb 7 '14 at 12:12
  • @mplungjan Who are the people who use it? How is it that I don't hear it? I read a great deal, including newspapers like the Guardian and Independent, and listen to BBC Radio 4. I watched Question Time last night with David Dimbleby. I didn't hear him say 'on a side note'! Nor Professor David Starkey, Tessa Jowell nor George Galloway! You hear all kinds of things in the crowd at a football match, but I don't include them in the lexicon of good English. – WS2 Feb 7 '14 at 12:31
  • Richard Coutice is a Senior Studio Manager and Digital Operations Specialist at the BBC: "On a side note, I also noticed that the clouds are the fluffy, Cumulus kind. The ones that make you think of a blue sky, a refreshing breeze and clean air. The sort of clouds that the Orb wrote about. But, I've been around for a while and I often suspect that Cumulonimbus might be more appropriate - dark, thunderous and anvil shaped, ready to dump on you from a great height, like the endlessly doomed Wile E. Coyote of the Roadrunner cartoons. ..... But I digress." – mplungjan Feb 7 '14 at 12:51
  • Jon Donnison - BBC Sydney correspondent: "On a side note, this "election bingo" from the Guardian is well worth a look and might liven up viewing" – mplungjan Feb 7 '14 at 12:53
  • Independent News > Business > Business Comment Mark Leftly: "On a side note, it shows how dangerous the bank levy is to the regions. It should not be glibly praised as part of a wider clampdown on fat cats in Canary Wharf and the Square Mile." – mplungjan Feb 7 '14 at 12:59

By the way, do you have any idea where my mackintosh is? I've looked everywhere.
By the way, I expect my bike back or somebody's photo is about to get destroyed.
By the way, I need my pen back.

On a side note, I've found my mackintosh.
On a side note, can I borrow your bike?
On a side note, do you have any idea when the party is?

On a side note, can I have a bite of that chocolate cake? It looks awfully good.

  • I'm afraid but this is not helpful at all. – Em1 Sep 17 '14 at 14:32

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