thou vs chiliad

thou and chiliad both are nouns.

Word	Noun	Adjective	Verb	Adverb
thou	Yes	No	No	No
chiliad	Yes	No	No	No

As nouns, thou and chiliad are synonyms defined as:

Other synonyms of thou include 1000, G, grand, K, M, one thousand, thousand, yard.

thou (noun)	chiliad (noun)
the cardinal number that is the product of 10 and 100	the cardinal number that is the product of 10 and 100