Assertion: symbol's letter | /r/HasProperty | retained in addition
Facets:
value: to the 24 letters
type: OTHER
Source sentences:
text: For this purpose, in addition to the 24 letters which by that time made up the standard alphabet, three otherwise obsolete letters were retained or revived: digamma ⟨Ϝ⟩ for 6, koppa ⟨Ϙ⟩ for 90, and a rare Ionian letter for [ss], today called sampi ⟨Ͳ⟩, for 900.