what is reticulum
Medical Definition of RETICULUM. 1. : the second compartment of the stomach of a ruminant in which folds of the mucous membrane form hexagonal cellsâcalled also honeycomb; compare abomasum, omasum, rumen.edical Definition of RETICULUM. 1. : the second compartment of the stomach of a ruminant in which folds of the mucous membrane form hexagonal cellsâcalled also honeycomb; compare abomasum, omasum, rumen.