The words entrance, entrants sound the same but have different meanings and spellings. Why do entrance, entrants sound the same even though they are completely different words?
The answer is simple: entrance, entrants are homophones of the English language.
The act or an instance of entering.
A means or point by which to enter.
Permission or power to enter; admission: gained entrance to medical school.
The point, as in a musical score, at which a performer begins.
Plural form of entrant.
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").