The hiragana syllable げ (ge). Its equivalent in katakana is ゲ (ge).

外科医: surgeon / 下界: lower world

one's real/natural hair (as opposed to a wig or extensions)

外科: surgery; surgical department

嚥下: swallowing

嚥下: swallow

歳々年々: year in, year out

(informal) idle girls' talk about love and romance

mokoshi: pent roof below the true roof of a pagoda, etc.

稟告: (rare, possibly obsolete) reporting (especially to a superior), (rare, possibly obsolete) a report (especially to a superior)