The words father, fother sound the same but have different meanings and spellings. Why do father, fother sound the same even though they are completely different words?
The answer is simple: father, fother are homophones of the English language.
A male person whose sperm unites with an egg, resulting in the conception of a child.
A man who adopts a child.
A man who raises a child.
A male parent of an animal.
a wagonload; a load of any sort.
an old English measure of lead or other metals, usually containing 19.5 hundredweight; a fodder.
Food for animals.
To feed animals (with fother).
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.