The words house, how's, hows sound the same but have different meanings and spellings. Why do house, how's, hows sound the same even though they are completely different words?
The answer is simple: house, how's, hows are homophones of the English language.
To take shelter.
A structure serving as a dwelling for one or more persons, especially for a family.
A household or family.
Something, such as a burrow or shell, that serves as a shelter or habitation for a wild animal.
how is.
how has.
Alternative spelling of hows. Plural form of how.
Plural form of how.
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").