noun
companion; fellow traveler; member of a party
Refers to someone who accompanies another on a journey, trip, or outing. Neutral term; can be used in formal and informal contexts.
彼は私の同行者として会議に出席した。
He attended the meeting as my companion.
ツアーの同行者はみんな親切だった。
All the fellow travelers on the tour were kind.
Compound of 同行 (どうこう, 'accompanying') + 者 (しゃ, 'person').