capital stock vs authorized shares

capital stock and authorized shares both are nouns.

Word	Noun	Adjective	Verb	Adverb
capital stock	Yes	No	No	No
authorized shares	Yes	No	No	No

As nouns, capital stock and authorized shares are synonyms defined as:

capital stock and authorized shares: the maximum number of shares authorized under the terms of a corporation's articles of incorporation

Other synonyms of capital stock include authorized stock.

capital stock (noun)	authorized shares (noun)
the maximum number of shares authorized under the terms of a corporation's articles of incorporation	the maximum number of shares authorized under the terms of a corporation's articles of incorporation
the book value of the outstanding shares of a corporation