(obsolete)The letterfita(Russianфита́(fitá)) orѳита́(fitá)). A consonantal letter intended to represent the Greek phoneme/θ/,which was approximated in Russian by/f/.Replaced by the letterф(f)in the spelling reform of 1917.
This letter was used in words ofGreekorigin in cases where Russian/f/derived from Greekθ(th)rather thanφ(ph).For example,орѳогра́фія(orfográfija,“orthography”),Ѳивы(Fivy,“Thebes”),etc.
In some words the pronunciation had changed to/t/under French and German influence. These were accordingly replaced withт(t)instead ofф(f).