What is the function of 一 in バスルーム and コンピュータ?


Is 一 in バスルーム and コンピュータ meant to indicate a drawn out vowel? Like ba-su-ruuu-
mu and kon-pi-yuuu-ta? Or is it a counter somehow? And it's the line radical
(<http://www.kanjidamage.com/kanji/1-one-line-radical-%E4%B8%80>) right, and
not a katakana like the other characters? Other examples include ヨーロッパ and
オーストラリア.

Wasn't sure if it was related to this question: [Syntactic Properties of "Bare
Numerals":
「一」in「其の一」](https://japanese.stackexchange.com/questions/73036/syntactic-
properties-of-bare-numerals-%e4%b8%80-in-%e5%85%b6%e3%81%ae%e4%b8%80)




It's very surprising to me that this hasn't been answered somewhere on the
site before, but after quite a bit of searching I can't find anything. This
may just be so basic that it has slipped between the cracks.

The `ー` in these words (and generally in katakana words) represents an
extension of the vowel before it. According to
[Wikipedia](https://en.wikipedia.org/wiki/Ch%C5%8Donpu), which is actually
fairly informative in this case, it's called a `長音符`.

> The chōonpu is usually used to indicate a long vowel sound in katakana
> writing, rarely in hiragana writing, and never in romanized Japanese.

That said, I hear it referenced colloquially as `伸ばし棒` almost exclusively (as
is mentioned on the [Japanese wiki
page](https://ja.wikipedia.org/wiki/%E9%95%B7%E9%9F%B3%E7%AC%A6)). I don't
actually know a good name for this in English; I would probably just call it a
vowel extension.




It's very surprising to me that this hasn't been answered somewhere on the
site before, but after quite a bit of searching I can't find anything. This
may just be so basic that it has slipped between the cracks.

The `ー` in these words (and generally in katakana words) represents an
extension of the vowel before it. According to
[Wikipedia](https://en.wikipedia.org/wiki/Ch%C5%8Donpu), which is actually
fairly informative in this case, it's called a `長音符`.

> The chōonpu is usually used to indicate a long vowel sound in katakana
> writing, rarely in hiragana writing, and never in romanized Japanese.

That said, I hear it referenced colloquially as `伸ばし棒` almost exclusively (as
is mentioned on the [Japanese wiki
page](https://ja.wikipedia.org/wiki/%E9%95%B7%E9%9F%B3%E7%AC%A6)). I don't
actually know a good name for this in English; I would probably just call it a
vowel extension.

