A trip that goes in one direction only (not round-trip).
今回は片道で飛行機を予約した。
This time I booked a one-way flight.
引っ越しだから荷物は片道で運べば十分だ。
It's a move, so transporting the luggage one-way will be enough.
片道の所要時間は約二時間です。
The one-way travel time is about two hours.
An abbreviation for a one-way ticket (i.e., a ticket valid only for a single direction).
駅で片道を一枚ください（＝片道切符）。
Please give me one one-way ticket at the station (i.e., a one-way ticket).
彼は片道で日本に来たまま帰る予定はないそうだ。
He came to Japan on a one-way ticket and apparently doesn't plan to return.