noun
relational expression; relation
Mathematical term for an expression that states a relationship between quantities, such as an equation, inequality, or functional relation.
この関係式を使って、未知の変数を求めることができる。
Using this relational expression, we can find the unknown variable.
物理の教科書には、エネルギーと質量の関係式が載っている。
The physics textbook contains the relational expression between energy and mass.