or ‧ gan ‧ is ‧ m /ˈɔːɡənɪz ə m $ ˈɔːr-/ BrE AmE noun [countable]
1 . an animal, plant, human, or any other living thing:
All living organisms have to adapt to changes in environmental conditions.
Genes operate together in determining the characteristics of an individual organism.
2 . a system made up of parts that are dependent on each other:
A society is essentially an organism.