thou vs one thousand

thou and one thousand both are nouns.

Word	Noun	Adjective	Verb	Adverb
thou	Yes	No	No	No
one thousand	Yes	Yes	No	No

As nouns, thou and one thousand are synonyms defined as:

thou and one thousand: the cardinal number that is the product of 10 and 100

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

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

thou (adjective)	one thousand (adjective)
	denoting a quantity consisting of 1,000 items or units