1. An abnormal enlargement of the liver and the spleen.
2. Etymology: the word hepatosplenomegaly is compounded from the following Greek roots: hepato- from hepatikos, "of the liver" + spleno, from splen (the spleen) + megaly from megas, "big" or "great" = "large liver and spleen".

The spleen is an organ located in the upper left quadrant of the abdomen just below the diaphragm and protected under the lower left ribs.