I came across a sentence that ends with ひとつだけ in a book and searching on jisho
gave me zero results
([https://jisho.org/search/ひとつだけ](https://jisho.org/search/%E3%81%B2%E3%81%A8%E3%81%A4%E3%81%A0%E3%81%91));
nor did searching for the individual parsing of what I remember from the audio
of the VN (i.e. hitotsu--DakE) give me any helpful results that would make
sense in context.

> しかも、出入り口は錆の浮いた鉄扉が **ひとつだけ** 。

TDLR: What does the sentence end(?) ひとつだけ mean in the above context and does
it have a general meaning when used at the end of a sentence as opposed to
being used elsewhere in the sentence?

Edit:

Context: Narrator is describing a unfamiliar room he wakes up in. I think that
ひとつだけ in the above context will not work as individual parsings as ひとつ most
likely means either the "adverbial noun – just" or the numeric one in the
above context that adverbially/numerically describes the 鉄扉 (iron door). The
next bit, だけ most likely is a particle ("only") but I don't see how the "only"
can affect the 鉄扉 as the ひとつ is already doing that to the "iron door". The
only way I can see both affecting 鉄扉 is if ひとつだけ is a qualifier sentence
(technically a qualifier phrase) being used in reverse-order.
CC BY-SA 4.0
2019-03-08T16:40:05.230
65911
2019-03-10T01:25:08.437
2019-03-08T17:26:04.743
26406
26406
question
word-requests word-usage sentence-final-particles particle-だけ
What does it mean to end a sentence with ひとつだけ?
Consider these simpler examples:

>   * リンゴ **は** 2個です。  
>  The number of apples is two.
>   * 参加者 **は** 3人です。  
>  The number of participants is three.
>   * 「箱の中には何がありますか？」「バナナ **が** 2本です。」  
>  "What is in the box?" "Two bananas."
>

Although "Apples are two" makes no sense in English, リンゴは2個です is a perfectly
valid way to tell the number of things in Japanese. As you already know, the
topic marker は is used for things already in the universe of discourse. が is
used to introduce a new item into the universe of discourse.

You can use both は and が at the same time:

> 参加者 **は** 日本人 **が** 3人です。  
>  Regarding (the number of) participants, there are three Japanese people.

You can drop です/だ to make a sentence look more compact and/or dramatic (体言止め):

> 参加者は3人。  
>  (There are) three participants.

You can add だけ (or のみ) to add the meaning of "only".

> 参加者は3人 **だけ** です。  
>  The number of participants is only three.

Combined together, we have something like:

> 参加者は日本人が3人だけ。  
>  Regarding participants, there are only three Japanese people.

This is exactly how your sentence in question is constructed, too.
CC BY-SA 4.0
2019-03-10T01:25:08.437
65930
2019-03-10T01:25:08.437
5010
65911
answer