that road (path, street, way, etc.)
that line (of business); that profession; that trade
love affairs; romance
その道のプロに相談した。
I consulted a professional in that field.
その道で生きていくのは容易ではない。
Making a living on that path is not easy.
音楽でその道を極めた人物の話を聞いた。
I heard the story of someone who mastered the path of music.