sicilicus

noun2

1. •
   A diacritic, resembling a 180°-rotated ‘C’ (i.e., being similar in appearance to ⟨ᵓ⟩), written atop a consonant to mark gemination, superseded in Classical Latin by doubling the letter representing the geminated consonant.

   • It is stated by grammarians that a sicilicus or laterally inverted Ⅽ, Ↄ, was placed above a consonant which was to be regarded as a doubled letter. — 1925
2. •
   A unit of weight equal to one quarter of an uncia.