Downfold

Part of speech: noun

Definitions

1. A geological fold in layered rock in which the strata bend downward, forming a trough-like structure
2. A downward bend or fold in a layer of material, especially in the earth's crust
3. A sagging curve in rock layers where the beds slope down toward a central point

Etymology: "Downfold" is a compound of "down" and "fold," joined to name a particular kind of land. "Fold" here carries its old sense of an enclosure or pen for livestock, most often sheep, and in the compound it points to a fold set on lower ground. The pairing is transparent: "down," in its sense of a stretch of open upland, combined with "fold," the walled or fenced pen where animals were kept at night. Put together, the term describes a sheepfold on the downs, the chalk and grassland hills of southern England where flocks grazed and were penned.