subderivative

from The Century Dictionary.

• noun A word following another in immediate grammatical derivation, or a word derived from a derivative and not directly from the root.

from the GNU version of the Collaborative International Dictionary of English.

• noun A word derived from a derivative, and not directly from the root

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun linguistics A word derived indirectly from a derivative of another
• noun mathematics The slope of a line that either touches, or is below the line of a convex function