I believe homotonic refers to the intonation when pronouncing the character (there are 4 intonations in Chinese, with a fifth "blank" tone). In this case, it is

I believe homotonic refers to the intonation when pronouncing the character (there are 4 intonations in Chinese, with a fifth "blank" tone). In this case, it is referring to words that are pronounced with the same sound, in the same intonation.