 Reversible reaction

A reversible reaction is a chemical reaction where the products can react to form the original reactants. In other words, the reaction can proceed in both the forward direction (reactants to products) and in the backward direction (products to reactants) under certain conditions. Reversible reactions are typically represented by a double arrow (⇌) in a chemical equation, indicating that the reaction can go in both directions.

I think these are the ones where $\Delta H\times \Delta S>0$, i.e. enthalpy and entropy push the reaction in different directions. And so we can use temperature to move the Chemical equilibrium back and forward.