one-way Definition

1a. Said of a road or street, etc: on which traffic is allowed to move in one direction only;
1b. Relating to or indicating such a traffic system.

Example: one-way sign
2. Said of a feeling or relationship: not returned or reciprocated.
3. Said of an agreement, etc: not involving any reciprocal action or obligation.
(N Amer, especially US)
4. Said of a ticket: valid for travel in one direction only; single (noun 4).
5. Said of a window, glass or mirror, etc: able to be seen through from one side only and which appears from the other side to be a mirror.