The three words are nouns; the three words contain a double letter.
That's an unusual question.
appaloosa
Several words contain three N's. "pennant" and "nonagon" are two of them.
There are many hundreds of words that contain those three letters (e.g. mudflow), but there are no English words that contain the letters MFW all together.
Caterpillar cake and country
The words he, she, and they are all personal pronouns; are all subjective forms; and all three contain the letters 'he'.
Ammonium, commandment, commemorate, commitment, communism, embalmment, mamma, mammal, minimum, mummy, and summertime are words. They contain three M's.
There are no words in th English language that contain three consecutive Es. There are no words in the English language that contain a triple grouping of any letter.
A sentence.
Three and nine hundredths
Zoo Zap Zig ?? Zag ?? Zac