Accompanying someone; being accompanied by someone; going together with someone.
小さな子どもは保護者の同伴が必要です。
Small children need to be accompanied by a guardian.
彼女はペットを同伴して旅行した。
She traveled with her pet.
会議には通訳の同伴をお願いした。
I asked to have an interpreter accompany me to the meeting.