John C. Zercher of Rockville underwent a coronary bypass operation last month, and as a result has enough free time on his hands to help this column worry about English usage.

Although "Capital" Beltway is the accepted spelling for our circumferential highway, some people spell it "Capitol" Beltway. The Capital Dog Training Club uses the "a" spelling but the Capitol Locksmith Co. is among the many firms that prefer the "o" spelling. Recognizing that many people are unsure which spelling is correct under which circumstances, a Silver Spring loan company lists itself in the phone book as Capital Finance Co. and also Capitol Finance Co. District Liner Zercher would therefore like to know what is now considered correct usage.

It is risky to write for next-day publication on the subject of what is considered proper usage "now." Writing about our ever-changing usage standards is like writing about the prevailing attitude among Wall Street traders. By the time your sage remarks get into print, they are out of date.

However, I like to live dangerously, so I will tell you what I perceive to be the current thinking on capital and Capitol and capitol .

A capitol, often spelled with a small "c," is a building in which a legislature meets. "The" Capitol, spelled with a big "C," is the building in Washington in which the United States Congress meets The big "C" is also known as an upper case or capital (note the spelling) "C."

Capital with an "a" has many meanings. It refers to wealth of all kinds, usually money or tangible things used in production. It also refers to any asset or advantage. In accounting, it means "net worth" - what's left after liabilities are deducted from assets in architecture, the top of a pillar or column is called a capital. And the world also refers to a city that is the official seat of the government of "a state, nation or other political entity."

Used as an adjective, capital can mean first foremost, chief, principal (not principle), first-rate, excellent ("a capital idea"), fatal, extremely serious ("a capital blunder"), relating to death or involving the death penalty ("capital punishment").

Obviously the two meanings that cause the confusion in spelling are the "o" that refers to a building and the "a" that refers to the city in which that building is located My own memory crutch - and you're welcome to borrow it - is that the Capitol dome has a rounded shape, like an "o."

If the roof of the Capitol ever develops leaks, as the one at the Kennedy Center did, and Congress decides to change it to a mansard design or some other kind of roof, we will have to begin looking for a new memory crutch. But let's face that problem when it arises. By that time John Zercher's chest will no longer be paining him and he'll be so busy with his normal activities that maybe he won't even have time to raise the issue again.