adjective
bilateral
bye-LAT-er-ul/ˌbaɪˈlætərəl/
Involving two sides or parties.
The two countries sign a bilateral agreement on trade.

Etymology
The pieces give the literal idea of having two sides. In dealings between parties or countries, those 'sides' are the two participants rather than physical surfaces.
In context
the india australia economic cooperation and trade agreement will further cement the already deep close and strategic relations between the two countries it will enhance bilateral trade in goods and services
More examples
- The examination reveals bilateral swelling in her knees.
- The talks aim to strengthen bilateral relations.
- The animal's body has bilateral symmetry.
Similar words
- mutual
- Emphasizes reciprocity rather than exactly two sides.
- multilateral
- Involves more than two parties or sides.