The words scyes, scythes, size, sighs sound the same but have different meanings and spellings. Why do scyes, scythes, size, sighs sound the same even though they are completely different words?
The answer is simple: scyes, scythes, size, sighs are homophones of the English language.
Plural form of <xref>scye</xref>.
Plural form of <xref>scythe</xref>.
Plural form of <xref>sigh</xref>.
Third-person singular simple present indicative form of <xref>sigh</xref>.
Considerable extent, amount, or dimensions.
Any of several gelatinous or glutinous substances usually made from glue, wax, or clay and used as a glaze or filler for porous materials such as paper, cloth, or wall surfaces.
To treat or coat with size or a similar substance.
Definitions from Wiktionary, Creative Commons Attribution/Share-Alike License., from The American Heritage® Dictionary of the English Language, 5th 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").