In biology, particularly cell biology, the term organelle is used to describe any one of a number of types of subcellular structures, historically identified through the use of some form of microscopy.
A few large organelles probably originated from endosymbiont bacteria:
... which 36.4% have children under the age of 18 living with them, 65.1% are married couples living together, 8.7% have a female householder with no husband present, and 23.4% ...