rennet (n.1) Look up rennet at
"inner membrane of a calf's fourth stomach," c. 1400, probably from an unrecorded Old English *rynet, related to gerennan "cause to run together," because it makes milk run or curdle; from Proto-Germanic *rannijanan, causative of *renwanan "to run" (see run (v.)). Compare German rinnen "to run," gerinnen "to curdle."
rennet (n.2) Look up rennet at
variety of apple, 1560s, from French reinette, literally "little queen," diminutive of reine "queen," from Latin regina (see Regina).