suet

plural suets

1. countableuncountableThe fatty tissue that surrounds and protects the kidneys; that of sheep and cattle is used in cooking and in making tallow.

   Some jays, chickadees, nuthatches, and titmice regularly feed at suet; others seem never to indulge.

   1998, Alan Pistorius, Everything You Need to Know About Birding and Backyard Bird Attraction

   2 more examples

   [T]he ſevvet of oxen […] is alſo good againſt the inflammation of the eares, the ſtupidity and dulneſſe of the teeth, the running of the eyes, the vlcers and rimes of the mouth, and ſtiffneſſe of the neck.

   1607, Conradus Gesnerus [i.e., Conrad Gessner]; Edward Topsell, “Of Cowes”, in The Historie of Foure-footed Beastes. […], London: […] William Iaggard, →OCLC, page 83

   Many seed-eating birds also need animal fat and protein which they obtain from insects, animal carcasses, and suet.

   1996, Laura Erickson, Sharing the Wonder of Birds with Kids