thousand vs one thousand

thousand and one thousand both are nouns.

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

As adjectives, thousand and one thousand are synonyms defined as:

thousand and one thousand: denoting a quantity consisting of 1,000 items or units

Other synonyms of thousand include 1000, k, m.

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

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

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

thousand (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

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