English

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Etymology

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From semi- +‎ forbidden.

Adjective

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semiforbidden (not comparable)

  1. (mathematics, physics) Partially forbidden
    • 2016, Zhenzhen Li, Hongyan Zhou, Lei Hao, Shufen Wang, Tuo Ji, Bo Liu, “Strong Optical and UV Intermediate-Width Emission Lines in the Quasar SDSS J232444.80-094600.3: Dust-Free and Intermediate-Density Gas at the Skin of Dusty Torus ?”, in arXiv[1]:
      The IEL component is presented in different emission lines, including the permitted lines \lya\  1216, \civ\  1549, semiforbidden line \ciii\  1909, and forbidden lines \oiii\  4959, 5007.