A small question

[Mycernius]

What is the correct name given to the bar used in Katakana to extend the vowel sound? All my books seem to only refer to it as a bar.

[strongvoicesforward]

What is the correct name given to the bar used in Katakana to extend the vowel sound? All my books seem to only refer to it as a bar.

In Japanese that is called "bou" or "yoko bou."

I usually use the former of the two words. Hope that helps.

[KrazyKat]

I typed it into JWPCe and it came up with:

ー 【ちょうおん】 (n) long vowel mark (usually only used in katakana)

[epigene]

I think it's called a "macron."

http://www.businessballs.com/diacriticalmarks.htm

[Glenn]

I learned it as the "vowel lengthening morpheme." Macron is the name of the bar over a letter in romanization, so if you're referring specifically to the character used in katakana then I think Kat has it right.

[Tensai Bakabon]

What is the correct name given to the bar used in Katakana to extend the vowel sound? All my books seem to only refer to it as a bar.
I can confirm KrazyKat's answer. This is a chouon. See http://www.sljfaq.org/w/Symbols :note: for a fairly comprehensive list of symbols like this.