Diving in (even if the parent doesn't care :) ):
The last sentence is the real challenge: Meanings depend 100% on writer and reader understandings. If two agree that 'homograph' means 'chicken poop', as long as they're the only ones communicating then 'chicken poop' it is; but if someone else reads it, our language subsystem fails.
Some dictionaries influence meaning by being prescriptive (e.g., American Heritage, IIRC); others report what has been understood by being descriptive (e.g., Oxford). The problem is, Wikipedia is neither: It represents the understandings of a few editors of unknown knowledge; it is neither descriptive nor prescriptive and we quickly get into chicken poop scenarios.
* Homograph, report Merriam-Webster and Oxford, means words with the same spelling but different meanings (or origin or pronunciation), e.g., the bow of a ship and a bow and arrow.
* Homoglyph doesn't appear in Oxford, Merriam-Webster, American Heritage, or any others (per Wordnik and OneLook), except Wiktionary. Wiktionary descriptively traces the word back to 1938 (though maybe with a different meaning in that case) and says it means a glyph with the same or similar appearance but different meaning. That still doesn't define a term for the entire string "ycornbinator.com", only the "rn", but close enough!