腔綫[kousen] gun rifling

アルファ線[arufasen] alpha rays
エックス線[ekkususen] X-ray
サイン曲線[sainkyokusen] sinusoid
スピード線[supiidosen] speed lines
緯線[isen] parallel

一次線輪[ichijisenrin] primary coil
一線[issen] line
一直線[icchokusen] straight line
一番線[ichibansen] track no. 1
一塁線[ichiruisen] first-base line

胸腔[kyoukou] thorax
口腔外科[koukuugeka] dental surgery
耳腔[jikou] inside the ear
体腔[taikou] body cavity
体腔壁[taikouheki] body wall

内腔[naikou] lumen (anatomical)
口腔[koukou] the oral cavity
鼻腔[bikou] the nasal cavity
腹腔[fukkou] abdominal cavity
口腔癌[koukougan] oral cancer