Maybe because of the fever, my mouth is extremely dry.
I have a mouth ulcer and eating is painful.
The dentist examined the inside of my mouth in detail.
To prevent cavities, it's important to keep the inside of your mouth clean.
After eating something hard, I got a small cut inside my mouth.
Standard kanji spelling for 'inside the mouth' or 'oral'.
Irregular kanji usage; 咥 is not standard for this meaning. Rarely encountered.
Compound of 口 (mouth) and 内 (inside). The reading こうない is the on'yomi of both characters.