Bacillus is a genus of BACTERIA that includes several species, such as Bacillus subtilis and Bacillus anthracis. It is a ROD-shaped, Gram-positive BACTERIUM that can form endospores, which are resistant to environmental conditions. The term 'bacillus' is often used interchangeably with the terms 'BUG', 'BACTERIA', 'BACTERIUM', 'MICROBE', 'GERM', 'SPORE', 'ROD', and 'rods'. These terms all refer to the same type of BACTERIA, which is known for its ability to survive in extreme environments.