What is the one way that the thermal energy of a system can be explained?

here is 1 way:

Explanation:

Meh explaination :1. Thermal energy refers to the energy contained within a system that is responsible for its temperature. Heat is the flow of thermal energy. A whole branch of physics, thermodynamics, deals with how heat is transferred between different systems and how work is done in the process (see the 1ˢᵗ law of thermodynamics).

Easy explaination:2. The energy of motion in the molecules of a substance.

Hard explanation: 3. Thermal energy is defined as the total of all kinetic energies within a given system.

Hope this helps!;)