zero-derivativehttp://www.oed.com/dictionary/zero-derivative_adj%3Ftab%3Dmeaning_and_usezero derivative, adj. & n.
Revised 2018

zero derivativeadjective & noun

Linguistics.
  1. 1948–
    a. adj. Designating a derivative in which the form of the original word is not altered; that marks such a derivative; b. n. a derivative in which the form of the original word is not altered.
    See note at zero derivation n.
    1. 1948
      We cannot say that song /soŋ/ is an alternant of sing /siŋ/ with the addition of a zero derivative suffix.
      Language vol. 24 427
    2. 1960
      There are quite a few vbs with French roots for which no French verbs are recorded and which may accordingly be treated as zero derivatives: feeble vb.., master vb, [etc.].
      H. Marchand, Categories Present-day English Word-formation v. 297
    3. 1976
      I believe..that act (noun) must be regarded as zero-derivative (actØ) from the corresponding verb.
      Archivum Linguisticum vol. 7 133
    4. 1999
      As far as the arrangement of derivatives, including zero-derivatives, is concerned, the principle..is to include all derivatives of a particular simple word in the entry for that word.
      A. P. Cowie, English Dictionary Foreign Learners i. 34

Originally published as part of the entry for zero, n. & adj.

zero, n. & adj. was revised in June 2018.