organelle

A differentiated structure within a cell, such as a mitochondrion, vacuole, or chloroplast, that performs a specific function.

a specialized part of a cell performing a specific function, usually visible under the microscope as a distinct object; it is analogous to an organ{2}, but on a microscopic scale.

A specialized structure found inside cells that carries out a specific life process (e.g. ribosomes, vacuoles).

a specialized part of a cell; analogous to an organ