Two-way (adjective)

1. Involving or allowing communication, interaction, or exchange in both directions.
2. Operating, moving, or working in both directions.

Origin:

The word 'two-way' is derived from the combination of the number 'two' and the noun 'way', meaning 'having two directions or sides'.

Examples:

1. A two-way street allows traffic to flow in both directions.
2. The radio has a two-way function, allowing communication in both directions.
3. The system has a two-way communication capability.
4. A two-way mirror allows one to see out but not in.
5. A two-way zipper allows for easy access from either direction.