Living organism (such as a bacteria, fungi, viruses) too small to be seen with naked eye but visible under a microscope. Also called microbe.

Use microorganism in a sentence

  • The astronauts were shocked and excited to discover a new species of microorganism on their most recent trip to the moon.

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  • The lake has has it's own ecosystem, it all starts from the microorganism to the top of the food chain.

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  • Under the microscope, we could see the microorganism and it was really interesting to study its behavior and how it worked.

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