The words sequence, sequents sound the same but have different meanings and spellings. Why do sequence, sequents sound the same even though they are completely different words?
The answer is simple: sequence, sequents are homophones of the English language.
A following of one thing after another; succession.
An order of succession; an arrangement.
A related or continuous series. See Synonyms at series.
Games Three or more playing cards in consecutive order; a run.
Plural form of sequent.
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.
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").