capital / capitol are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
capital: (noun) assets available for use in the production of further assets. (noun) wealth in the form of money or property owned by a person or business and human resources of economic value. (noun) a seat of government. (noun) one of the large alphabetic characters used as the first letter in writing or printing proper names and sometimes for emphasis. (noun) a center that is associated more than any other with some activity or product. (noun) the federal government of the United States. (noun) the upper part of a column that supports the entablature. (adjective) first-rate. (adjective) of primary importance. (adjective) uppercase.
capitol: (noun) a building occupied by a state legislature. (noun) the government building in Washington where the United States Senate and the House of Representatives meet.
capital: k·AE·p·ah·t·ah·l
capitol: k·AE·p·ih·t·ah·l
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)