The words waits, weights sound the same but have different meanings and spellings. Why do waits, weights sound the same even though they are completely different words?
The answer is simple: waits, weights are homophones of the English language.
Plural form of wait.
A group of singers or musicians performing in the streets, especially around Christmas.
Third-person singular simple present indicative form of wait.
Any collection of weighted objects, such as dumbbells or barbells, used for exercise and training the muscles.
Plural form of weight.
Third-person singular simple present indicative form of weight.
Definitions 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.
If they are spelled the same then they are also homographs (and homonyms); if they are spelled differently then they are also heterographs (literally "different writing").