Webster 1913 Edition
rennan, to run, cf.
gerinnanto curdle, coagulate. √11. See
The inner, or mucous, membrane of the fourth stomach of the calf, or other young ruminant.
Webster 1828 Edition
The concreted milk found in the stomach of a sucking quadruped, particularly of the calf. It is also written runnet, and this is the preferable orthography.