Accompanying someone; going together. Often used as '同行する' to indicate moving together with someone.
出張に部長が同行することになった。
The manager will accompany me on the business trip.
医者の説明に家族が同行して、質問した。
A family member accompanied the patient to the doctor's explanation and asked questions.
危険な場所へは必ず二人以上で同行するように指示が出た。
We were instructed to always go in groups of two or more to dangerous places.
ツアーガイドが参加者と同行し、案内を行った。
The tour guide accompanied the participants and provided guidance.
In banking contexts, refers to 'the same bank' or 'the bank in question' (formal/industry usage).
振込先は同行の本店口座にしてください。
Please transfer the payment to the bank's head office account (the same bank).
この手数料は同行間の送金には適用されない。
This fee does not apply to transfers between the same bank.
同行の担当者に詳細を確認したところ、支払いは間もなく処理されるとのことだった。
When I checked with the person in charge at the same bank, they said the payment would be processed soon.