Cocci (singular - coccus, from the Latin coccinus (scarlet) an derived from the Greek kokkos (berry) ) are any microorganism (usually bacteria) whose overall shape is spherical or nearly spherical. Describing a bacterium as a coccus, or sphere, distinguishes it from bacillus, or rod. This is the first of many taxonomic traits for identifying and classifying a bacterium according to binomial nomenclature.