An organism, usually a bacterium, that needs oxygen to survive and grow.
From aero- (air/oxygen) + -be (from Greek bios, life); literally 'air-lifer'; coined in late 1800s microbiology to distinguish oxygen-dependent organisms.
Most organisms you know — including you! — are aerobes; we literally can't live without breathing oxygen. The discovery of aerobes versus anaerobes completely revolutionized medicine because doctors realized some infections were caused by organisms that thrived specifically in oxygen-free environments.
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