English Reference
noun

organism

n.
US /ˈɔɹɡəˌnɪzəm/ UK /ˈɔːɡənˌɪzəm/ or·gan·ism UK spelling organism's, organism's

  1. 01 B2 Upper Intermediate Science

    any living thing, from a tiny germ to a giant whale.

    an individual living system, such as an animal, plant, fungus, or bacterium, capable of response to stimuli, reproduction, growth, and homeostasis.

    Simple

    The pond is full of tiny organisms that you can only see with a microscope.

    In context

    Biologists are still discovering new marine organisms in the deepest parts of the ocean that survive without any sunlight.

    Usage

    Countable noun; often used in scientific or academic contexts rather than casual conversation.

  2. 02 C1 Advanced AcademicFormal

    a large system or organization that has many parts working together like a body.

    a complex structure or organization with interdependent parts whose functions are determined by their relation to the whole.

    Simple

    The government is a massive organism that changes very slowly.

    In context

    The city functions as a social organism, where transport, housing, and commerce must remain in balance to ensure the health of the community.

    Teacher's tip

    This is a metaphorical use; learners should use it when describing how different departments or sections of a large group interact.

Scientists are still trying to understand when the first eukaryotes appeared on Earth and how those organisms helped set the stage for complex life.

ScienceDaily· 17 Aug 2026

Unlike bats or crickets or frogs or whales, earthworms and other soil organisms do not shout to find their way around, nor trill and whoop to attract mates.

Aeon· 17 Aug 2026

First attested in 1701; from organ + -ism, from Ancient Greek ὄργανον (órganon, “a tool, instrument”), from Proto-Indo-European *werǵ- (“work”). Compare New Latin organismus.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin la-new organismus
Level B2 · Upper Intermediate
Frequency Frequent
Updated