While many people new to the field of microbiology like to use the terms rods and spheres, you prefer the correct terminology that is currently in use to describe the morphology of bacteria, which is also utilized in naming newly discovered species of bacteria. Shape designations for the cells are based on Latin or Greek description of the cellular shape and configurations.

1. Spherical shape: coccus: from the Latin coccinus (meaning scarlet) and derived from the Greek kokkos (meaning berry).

2. Rod shape: bacillus: from the late Latin and diminutive of the Latin word baculus (meaning stick; walking stick).

Explanation:

Bacteria are generally classified by their shape and morphology. Numerous microbiologists use the words "rod" or "rod-shaped" and "sphere" or "sphere-shaped" to refer to the morphology of bacteria, these are actually coloquial termd. The correct names for the shapes of bacteria come from Latin and Greek, as many scientific names do, this is known as their etymology, that is, their origin.

The proper or scientific name of a spherical shape or the word 'sphere', is coccus, which comes from the Latin coccinus (meaning scarlet) and derived from the Greek kokkos (meaning berry).

The proper or scientific name of a 'rod' shape is bacillus, which derives from the late Latin and diminutive of the Latin word baculus (meaning stick; walking stick).