What's the difference between tradition and convention in English?

Legendary may also be traditional, but traditional is not necessarily legendary.

Customary achievement is "the behavior that most people in society think is correct or appropriate", but it does not necessarily have a long historical background. So "treaty, agreement" is an agreement. Tradition is a "long-standing custom or habit".

Therefore, although their adjectives can be translated into "traditional and conventional", the two words cannot be confused in some sentences because the meaning of conventional is wider than traditional.

For example, conventional weapons are conventional weapons but there are no traditional weapons.