A spherical bacterium is a type of bacteria that has a round shape. The two crossword solutions for this term are Staph and Coccus, both of which are five and six letters respectively. Staph is short for Staphylococcus, which is a genus of Gram-positive bacteria that can cause a variety of infections. Coccus is a genus of Gram-positive bacteria that are typically found in soil and water. Both genera are spherical in shape and can cause various illnesses in humans.