声門 is read as せいもん (seimon) and means glottis.
せいもん
seimon
せいりょう
(vocal) volume
せいたい
vocal cords
せいいき
range (of voice)
こえがうらがえる
to crack (person's voice)
もん
branch of learning based on the teachings of a single master
ぶもん
division (of a larger group)
にゅうもん
entering through a gate
めいもん
prestigious school, organization, business, etc.
せんもん
sole interest
と
door (esp. Japanese-style)
かんもん
barrier
main gate