The correct spelling of the word "Fillys" is actually "Fillies". The word "fillies" is the plural form of the noun "filly", which refers to a young female horse. The pronunciation of "Fillies" is /ˈfɪliz/, with the stress on the second syllable. The sound of the letter "y" in "Fillies" is pronounced as an "i" sound, which is why there is no "y" in the correct spelling of the word. It's important to spell words correctly to avoid confusion and ensure proper communication in written language.
The word "fillys" is a misspelling or a variant spelling of the word "fillies". The term "fillies" is derived from the Old English word "fylle", meaning a young female horse. It has its roots in the Proto-Germanic word "fulljō", which also referred to a young mare. The term gradually evolved in Middle English to become "filly" and has remained in use to refer to a young female horse, typically under four years of age.