noun, noun, used as a suffix
transport service; flight; train or ferry run
Used for a scheduled transport service, especially as a counter-like suffix or noun in expressions such as 東京行きの便, 次の便, 第一便.
東京行きの便を予約した。
I booked a service to Tokyo.
次の便は午後三時に出発します。
The next flight leaves at three in the afternoon.
noun, noun, used as a suffix
Common in compounds and suffix-like uses for mail or delivery methods, such as 航空便, 船便, 速達便, and 宅配便. Standalone 便 meaning a letter can sound more formal or old-fashioned than 手紙.
この書類は航空便で送ってください。
Please send these documents by airmail.
荷物は船便で届く予定です。
The package is scheduled to arrive by sea mail.
noun, noun, used as a suffix
A somewhat formal or old-fashioned use meaning an occasion or opportunity to do something; often seen in phrasing like 上京の便 or 便がある.
来月上京の便がありますので、その際にお届けします。
I will have an opportunity to go to Tokyo next month, so I will deliver it then.