The words psi, sie, sigh, scye, scythe sound the same but have different meanings and spellings. Why do psi, sie, sigh, scye, scythe sound the same even though they are completely different words?
The answer is simple: psi, sie, sigh, scye, scythe are homophones of the English language.
pounds per square inch
Parapsychological phenomena or abilities considered as a group.
The 23rd letter of the Greek alphabet. See Table at alphabet.
an armhole (or, occasionally, a leghole) in tailoring and dressmaking
To cut with or as if with a scythe.
An implement consisting of a long, curved single-edged blade with a long bent handle, used for mowing or reaping.
Gender-neutral (or multigendered) subject pronoun, grammatically equivalent to the gendered pronouns he and she, or singular they
To strain, as milk; filter.
The act or sound of sighing.
Archaic To lament.
To express with or as if with an audible exhalation.
To feel longing or grief; yearn: sighing for their lost youth.
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.