The term 'Tiny Building Block' can be described as an ATOM, which is a four letter word. An ATOM is the smallest unit of matter that still retains its chemical properties. Atoms are made up of protons, neutrons, and electrons, and they are the building blocks of all matter. Atoms are so small that they cannot be seen with the naked eye, but they are essential for the formation of molecules and other structures. Therefore, Tiny Building Blocks can be thought of as atoms, which are the fundamental units of matter.