this field of study

a son's duty to his parents

The Inner Path; a term derived from the Sanskrit referring to any orthodox Buddhist doctrine which "treads the inner path" to enlightenment.

conductor (something which can transmit electricity, heat, light or sound)

the inside of prefecture of Japan which is suffixed "道" (Dō) / the inside of Hokkaido

(obsolete) tunnel

flue

diversion; deceptive action used to distract someone

bedouin

The hiragana syllable ど𛅒 (dwo). Its equivalent in katakana is ド𛅦 (dwo).