bacillus
noun
ba·cil·lus bə-ˈsi-ləs 
plural bacilli bə-ˈsi-ˌlī
also -lē
1
: any of a genus (Bacillus) of rod-shaped gram-positive usually aerobic bacteria producing endospores and including many saprophytes and some parasites (such as B. anthracis of anthrax)
broadly : a straight rod-shaped bacterium
2
: bacterium
especially : a disease-producing bacterium
Example Sentences
Recent Examples on the Web The ReencleMicrobe mix at the heart of this process contains rice husks, vermiculite, nonpathogenic bacillus bacteria, ammonium sulfate, and wood pellets, according to the company. 
Richard Baguley, Wired, 31 Mar. 2022 Scientists postulate that the bacillus originated in some lower animal and jumped to humans. Washington Post, 23 Mar. 2022 The technique is a deadly bacteria bacillus, one that first emerges in one corner of the world and is spreading far and wide, with consequences that could prove disastrous for hundreds of millions of people. Frida Ghitis, CNN, 14 Sep. 2021 Now nearly two dozen clinical trials around the world are underway to determine whether the bacillus Calmette-Guérin (BCG) vaccine against tuberculosis could protect against COVID-19. Melinda Wenner Moyer, Scientific American, 27 Oct. 2020 Once the bacillus and its antibacterial medication were discovered, the TB patient was no longer exiled but treated within, and assimilated by, the same socioeconomic framework as the rest of us. Joseph Osmundson, The New Republic, 30 July 2020 The masses of poor religious Jews in Poland were almost accidental to the effort; the real target was the élite, who brought with them the bacillus of cosmopolitanism. Adam Gopnik, The New Yorker, 15 June 2020 Most doctors assumed the disease was caused by a bacterium; the recently discovered Pfeiffer’s bacillus (Haemophilus influenzae), which was sometimes present in pathology specimens, was the prime suspect. Wendy Moore, Time, 28 Apr. 2020 Also, the early use of face masks which predated Wu's discovery of the bacillus as pneumonic. Paul French, CNN, 18 Apr. 2020 See More
Richard Baguley, Wired, 31 Mar. 2022 Scientists postulate that the bacillus originated in some lower animal and jumped to humans. Washington Post, 23 Mar. 2022 The technique is a deadly bacteria bacillus, one that first emerges in one corner of the world and is spreading far and wide, with consequences that could prove disastrous for hundreds of millions of people. Frida Ghitis, CNN, 14 Sep. 2021 Now nearly two dozen clinical trials around the world are underway to determine whether the bacillus Calmette-Guérin (BCG) vaccine against tuberculosis could protect against COVID-19. Melinda Wenner Moyer, Scientific American, 27 Oct. 2020 Once the bacillus and its antibacterial medication were discovered, the TB patient was no longer exiled but treated within, and assimilated by, the same socioeconomic framework as the rest of us. Joseph Osmundson, The New Republic, 30 July 2020 The masses of poor religious Jews in Poland were almost accidental to the effort; the real target was the élite, who brought with them the bacillus of cosmopolitanism. Adam Gopnik, The New Yorker, 15 June 2020 Most doctors assumed the disease was caused by a bacterium; the recently discovered Pfeiffer’s bacillus (Haemophilus influenzae), which was sometimes present in pathology specimens, was the prime suspect. Wendy Moore, Time, 28 Apr. 2020 Also, the early use of face masks which predated Wu's discovery of the bacillus as pneumonic. Paul French, CNN, 18 Apr. 2020 See More Word History
Etymology
New Latin, from Medieval Latin, small staff, rod, diminutive of Latin baculus staff, alteration of baculum
First Known Use
1868, in the meaning defined at sense 1
Phrases Containing bacillus
Medical Definition
bacillus
noun
ba·cil·lus bə-ˈsil-əs
plural bacilli
-ˌī also -ē
1
a
capitalized : a genus of rod-shaped gram-positive endospore-producing usually aerobic bacteria of the family Bacillaceae that include many saprophytes and some parasites (as B. anthracis of anthrax)
b
: any bacterium of the genus Bacillus
broadly : a straight rod-shaped bacterium
2
: bacterium
especially : a disease-producing bacterium