means An outcrop is a section of bedrock or rock formation that pokes up through the soil or vegetation to become visible at the earth's surface.

from A transparent English compound of "out" plus "crop" — built from the same family of "crop" meaning to appear, sprout, or come to the surface (as in "crop up"). It surfaced as a geological term in the 19th century, when miners and surveyors needed a word for where a vein or seam "cropped out" of the ground; the noun simply froze that phrase into a single thing.