noun.a complex structure of interdependent and subordinate elements whose relations and properties are largely determined by their function in the whole

• The nation is not merely the sum of individual citizens at any given time, but it is a living organism, a mystical body … of which the individual is an ephemeral part …
• a multicellular organism

noun.an individual constituted to carry on the activities of life by means of parts or organs more or less separate in function but mutually dependent: a living being