How are volcanic bombs lapili and ash relate to tephra?

Volcanic bombs, lapilli, and ash are all types of tephra, which refers to any fragments of volcanic rock and lava that are explosively ejected during a volcanic eruption. Volcanic bombs are large, aerodynamic clasts that cool in flight, lapilli are small rock fragments ranging from 2 to 64 mm in size, and ash consists of fine particles less than 2 mm in diameter. Together, they make up the different-sized components of tephra fallout from volcanic eruptions.