The words mail, male sound the same but have different meanings and spellings. Why do mail, male sound the same even though they are completely different words?
The answer is simple: mail, male are homophones of the English language.
Materials, such as letters and packages, handled in a postal system.
Postal material for a specific person or organization.
Material processed for distribution from a post office at a specified time: the morning mail.
A system by which letters, packages, and other postal materials are transported. Used in the plural with the.
Of, relating to, or designating the sex that has organs to produce spermatozoa for fertilizing ova.
Characteristic of or appropriate to this sex; masculine.
Consisting of members of this sex.
Virile; manly.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition 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").