bilateral

Everyday

1. (politics, formal) Involving two sides, groups or countries, as in a bilateral agreement. tree →
2. (science, medicine) Having to do with both sides of the body, as in bilateral symmetry. tree →

In the lessons

In politics and news, a bilateral treaty or meeting is between two countries. In science, animals like humans and butterflies have bilateral symmetry: the left and right halves are mirror images. In maths, that is a line of symmetry down the middle.

Examples

• The two countries signed a bilateral trade deal. tree →
• Humans have bilateral symmetry. tree →
• A butterfly's wings show bilateral symmetry. tree →
• The prime ministers held bilateral talks. tree →
• The doctor said the infection was bilateral, in both ears. tree →
• A starfish does not have bilateral symmetry; it has five-way symmetry. tree →

Note

«Bi-» means two; «lateral» means side. Compare: unilateral (one side), multilateral (many sides). Formal word.