1) Geological phenomenon 
Endogenous substances are those that originate from within an organism, tissue, or cell. Endogenous viral elements (EVEs) are DNA sequences derived from viruses that are ancestrally inserted into the genomes of germ cells. These sequences, which may be fragments of viruses, or entire viral genomes (proviruses), can persist in the germline, being p...
• (n.) Growth from within; multiplication of cells by endogenous division, as in the development of one or more cells in the interior of a parent cell.
En·dog'e·ny noun [ See Endogenesis .] (Biol.) Growth from within; multiplication of cells by endogenous division, as in the development of one or more cells in the interior of a parent cell. 
noun a geological phenomenon below the surface of the earth
development or growth from within.