開かい口こう

noun, noun or participle which takes 'suru', intransitive verb

opening; aperture

A physical opening or aperture, often in technical contexts such as pipes, structures, lenses, or cameras. As 開口する, it can describe an opening being open or gaping in a technical way.

• 作さ業ぎょう後ご、配はい管かんの開かい口こうをふさいだ。

  After the work, we covered the opening in the pipe.

• レンズの開かい口こうが大おおきいほど、多おおくの光ひかりを取とり込こめる。

  The larger the lens aperture, the more light it can take in.

noun, noun or participle which takes 'suru', intransitive verb

opening one's mouth

Formal or technical wording for opening the mouth, especially in medical, dental, or examination contexts; everyday speech more often says 口を開ける.

• 歯し科か医いに「大おおきく開かい口こうしてください」と言いわれた。

  The dentist told me, "Please open your mouth wide."

noun, noun or participle which takes 'suru', intransitive verb

beginning to speak; opening one's mouth to speak

A written or somewhat formal use meaning to start speaking after silence. It is also familiar in the set expression 開口一番, meaning 'the first thing someone says.'

• 彼かれはしばらく黙だまったあと、ようやく開かい口こうした。

  After staying silent for a while, he finally began to speak.

• 彼かの女じょは開かい口こう一いち番ばん、「本ほん当とうにすみません」と謝あやまった。

  The first thing she said was, "I'm truly sorry."

noun-modifying (irregular)

open; wide; broad

Limited prenominal or compound-form use meaning open or wide-open, as in terms such as 開口状態 or 開口母音. It is not normally used as a free adjective like English 'open.'

• 検けん査さ中ちゅうは開かい口こう状じょう態たいを保たもってください。

  Please keep your mouth open during the examination.

• 音おん声せい学がくでは、開かい口こう母ぼ音いんは口くちの開ひらきが大おおきい母ぼ音いんを指さす。

  In phonetics, an open vowel refers to a vowel pronounced with a wide mouth opening.