Recently, I posted a puzzle on Puzzling.SE.

The puzzle describes a prison containing thousands of hallways which all run next to each other, like the pipes in a pan flute. In my description of the prison, I wrote that most of the hallways have a door which leads to the adjacent hallway.

Someone wrote in the comments that my use of the word "the" is incorrect. After all, most of the hallways have two adjacent hallways, and so I can't write "the adjacent hallway"; I have to write "an adjacent hallway" or "one of the adjacent hallways".

However, I could swear that it's reasonably common in English to write things like "the adjacent room" and "the adjacent lot" even when there are multiple adjacent rooms and multiple adjacent lots, and no way for the reader to determine exactly which room or lot was meant.

I could very easily imagine someone saying "I was lecturing once when I heard a strange noise from the adjacent classroom", even when there are two adjacent classrooms; and "there are trees on the line between this lot and the adjacent lot", even when there are several adjacent lots. To me, if you replace "the" with "an" in either of those examples, it sounds bit like you're trying to draw the reader's attention to the existence of a new classroom or lot that they weren't aware of before.

Is my thinking correct? Is it really appropriate to write "the adjacent room" when there are several adjacent rooms, or am I just imagining things?

I'm interested primarily in whether or not "the" is actually used this way by careful writers, not in what textbooks for English students have to say about the matter.

  • 1
    Don't you think "reasonably common" mistakes are no justifcation for getting things wrong? If you want to be correct then no, you may not use "the adjacent hallway". You do need "an adjacent hallway" or "one of the adjacent hallways"… If you don't mind being seen as incorrect… or… uh… "wrong", use what words you wish… Jun 1, 2020 at 22:22
  • @RobbieGoodwin Of course I think that reasonably common mistakes are no justification for getting things wrong. I'm not asking if it's a reasonably common mistake; I'm asking if it's the way careful writers habitually write. Jun 1, 2020 at 22:29
  • Then why not do the research? Why not use any of the tools available through any search engine to show how all writers habitually write, then make your own conclusion about what careful writers do differently? Alternatively, why not drop the Question as broadly unanswerable? Jun 1, 2020 at 22:40
  • In any case, I've edited the question to make it more similar to other well-received [grammaticality] questions. I'm now simply asking "is this correct?" instead of explicitly asking what careful writers do. Jun 1, 2020 at 23:11
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    'By careful writers' and 'in logic classes' don't always boil down to the same thing. English interpretation is often governed by pragmatics (what 95+% of competent native speakers would understand by a statement etc). If you're going into more precisionist interpretations, it's only fair to clarify which rules you've chosen to use. So on ELU, this must be 'answer arbitrary / dependent on specific language usages needing spelling out by the inquisitor / opinion-based'. Aug 12, 2021 at 11:40

2 Answers 2


One matter hasn't been addressed so far: the text the OP discusses is a puzzle. If you're listening to someone telling a story, and they said "I was lecturing once when I heard a strange noise from the adjacent classroom" (an example by the OP), then you might not trouble to ask them to clarify whether it was the one on the left, the right, or wherever. You might take it for granted that this detail doesn't matter to your appreciation of their story.

By contrast, a puzzle is different. The setter (the person posing the puzzle) needs to make it clear what information the solver is told, and what they are not told. Are the hallways connected in pairs but the pairs separate? Or is each hallway connected to both its neighbours? Or perhaps the setter specifically intends not to tell the solver. The solver can't glean this from context, because the puzzle statement is the entire context. In such a situation, accuracy of wording is critical.


I've found several uses of the phrase "the adjacent room", in cases where there are multiple adjacent rooms and no way of identifying a particular one, in printed books from mainstream publishers.

Given these citations, I can only conclude that this usage is perfectly grammatical and correct.

All of these are from Google Books.

Jones, Thomas J. A. Professional Management of Housekeeping Operations. United Kingdom, Wiley, 2007, p. 216:

[...] engineer with a bolt cutter in preparation for cutting the chain on the door.

There are two specific exceptions to the concerns stated, both of which should be considered before using the emergency master key or the bolt cutter. The room may have been sold as part of a suite that adjoins the adjacent room.

Ermann, Michael. Architectural Acoustics Illustrated. United States, Wiley, 2015, p. 179:

Design rooms that are not noise sensitive as buffer zones between noisy spaces and quiet spaces. For instance, place a row of closets, utility rooms, vestibules, and bicycle storage rooms between residential units. Experience suggests that the room two-doors-down is much quieter than the adjacent room, so insert buffer rooms to effectively move noisy rooms “two doors down.”

Jellison, Judith. Including Everyone: Creating Music Classrooms Where All Children Learn. United States, Oxford University Press, 2015 (no page number):

We've also experienced times when we cannot concentrate on a task because of distracting sounds from others in the same room, from a malfunctioning heating or cooling system, or from musicians practicing in the adjacent room.

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    "Given these citations, I can only conclude that this usage is perfectly grammatical." - But grammatical and semantically correct are not the same thing. It's possible to be grammatically correct but completely nonsensical. (Not that the examples you found are nonsensical, but "grammatical" is not the bar you need to clear here.)
    – nnnnnn
    Jul 18, 2020 at 2:35
  • @nnnnnn Yep, I suppose that's true. I changed it to say "grammatical and correct". Jul 18, 2020 at 3:37
  • In each of the quotes, the context seems to imply a specific adjacent room.
    – Lawrence
    Aug 17, 2020 at 9:18

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