Here's why:
* Homonyms are words that are spelled the same but have different meanings. For example, "bear" (the animal) and "bear" (to carry).
* Homophones are words that sound the same but are spelled differently and have different meanings. For example, "there," "their," and "they're."
"Progress" doesn't share any of these characteristics with any other word. It has a unique spelling and a unique meaning.