organism

noun organism

• creature — You can refer to any living thing that is not a plant as a creature, especially when it is of an unknown or unfamiliar kind. People also refer to imaginary animals and beings as creatures.
• animal — An animal is a living creature such as a dog, lion, or rabbit, rather than a bird, fish, insect, or human being.
• plant — any member of the kingdom Plantae, comprising multicellular organisms that typically produce their own food from inorganic matter by the process of photosynthesis and that have more or less rigid cell walls containing cellulose, including vascular plants, mosses, liverworts, and hornworts: some classification schemes may include fungi, algae, bacteria, blue-green algae, and certain single-celled eukaryotes that have plantlike qualities, as rigid cell walls or photosynthesis.
• virus — an ultramicroscopic (20 to 300 nm in diameter), metabolically inert, infectious agent that replicates only within the cells of living hosts, mainly bacteria, plants, and animals: composed of an RNA or DNA core, a protein coat, and, in more complex types, a surrounding envelope.
• bacterium — Bacterium is the singular of bacteria.