Staphylococcus aureus

Etymology
Staphylococcus aureus:;

staphylo: "bunch of grapes" (from greek σταϕυλή, meaning "bunch of grapes")

coccos: "berry" (from greek κόκκος, meaning "berry")

aureus: "golden" (from latin aureus, meaning "golden")

Explanation
The bacteria Staphylococcus aureus looks like a cluster of small berry-shaped cells (coccos) that are arranged in a formation which resembles a bunch of grapes (staphylo), and appear golden (aureus) in colour when grown on a petri dish.