Bacilli

Part of speech: noun

Definitions

1. A type of rod-shaped bacteria known for their role in various diseases and environmental processes
2. Microorganisms characterized by cylindrical shapes that can be pathogenic or beneficial in ecosystems
3. Bacteria that are elongated and can reproduce through binary fission, found in diverse habitats and affecting health and fermentation

Etymology: "Bacilli" is the plural of "bacillus," and the singular already carried a meaning before anyone applied it to microbes: in Latin, "bacillus" was a little staff or wand. It is a diminutive of "baculum," meaning stick, staff or walking stick, so the name rests on a simple image of something small and rod-shaped. The word reached modern science as a learned borrowing, taken directly from Latin rather than arriving through everyday speech. Microbiologists chose it because the organisms looked like tiny rods under the early microscope, so the old Latin picture of a little stick fit them exactly.