Compounds of 開口

• 開口
  (n,vs) (1) opening
  aperture (e.g. camera)
  (2) opening one's mouth
  beginning to speak
  (adj-f) (3) open
  broad
  (P)
• 開口音
  (n) (1) (of Chinese) pronunciation of kanji without a medial between the initial consonant and center vowel
  (2) (of Japanese) the long "o" vowel arising from combination of the "a" and "u" sounds
• 開口数
  (n) numerical aperture (in photography)
• 開口部
  (n) aperture
• 開口率
  (n) aperture ratio
• 開口一番
  (n-adv) at the very beginning of one's speech
  the first thing (one) says after opening the mouth
• 読取り書込み開口部
  (n) (comp) read-write slot
  read-write opening