Capitol is a term used for a specific building (or set of buildings) related to state government. More specifically, the Capitol (with an upper-case “C”) usually refers to the specific building in Washington, DC where the Congress of the United States meets. It can sometimes refer to a government building in other countries, but when you see “Capitol” written, it’s usually talking about the American building.
Capital, on the other hand, is a term that actually has several meanings. It can refer to the city that is the official seat of government for a district, county or country. For instance, Beijing is the capital city of China and Victoria is the provincial capital of British Columbia. Capital can also refer to capital letters, meaning those that are upper-case (ABC), as opposed to lower case (abc).
In the context of finance, capital would refer to the accumulated wealth that a person or organization may have. This can refer to money, property or both. If you own 50% of a one million dollar company, then you could say that you have $500,000 worth of capital. Given this connotation of value, it’s also understandable that capital can be used as an adjective to mean of excellent or first-rate quality. It can also refer to the primary or main aspect, as in capital concerns or capital importance.
More often than not, if you’re not sure whether you should use “capital” or “capitol,” you’ll probably want to use “capital” unless you are referring to that particular government building in Washington, DC. Outside of that context, “capitol” is very rarely used.
Do you have a suggestion for a Grammar 101 post? Is there a particular grammar or spelling question of capital interest to you? Don’t hesitate to post a comment below to let me know and I”ll add it to the queue.