The words tire, tyer, tyre sound the same but have different meanings and spellings. Why do tire, tyer, tyre sound the same even though they are completely different words?
The answer is simple: tire, tyer, tyre are homophones of the English language.
To grow weary.
To grow bored or impatient.
To diminish the strength or energy of; fatigue.
To exhaust the interest or patience of; bore.
Dated form of tier. (person or device that ties)
Chiefly British Variant of tire2.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition, from Wiktionary, Creative Commons Attribution/Share-Alike License and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.