root end
/ˌruːt ˈɛnd/noun
1The end of a plant stem, seed, etc., which is next to the root, or from which the root develops.
2In extended use: the end of a hair, nail, etc., nearer to the root; the extremity of a root of a tooth.
Origin
Late 16th century; earliest use found in William Harrison (1535–1593), historian and topographer. From root + end.