At times, George Washington University's current zoning battle sounds rather like a Scotish clan war, filled with passionate rallying cries that nobody else understands. Housewives and retirees speak earnestly of F.A.R.'s and P.U.D.'s.An attorney for the university stood before the Zoning Commission last week and cried, his voice ringing with indignation, "This is the only location in the entire District of Columbia where R5C land abuts the C4 zone!"

What that means, in English, is that GW's residentially-zoned block sits right next to a block zoned for downtown commercial use. It is an unusually abrupt transition. Downtown zoning means dense, heavily trafficked buildings - department stores, massive offices, light industry like The Washington Post's building.

Residential zoning means just that. No businesses. Normally the downtown area is bufferred by zones that allow for smaller and quieter businesses, but on this block, downtown marches right up to the magnolia tree in Mildred Obear's front yard.

Backers of the World Bank's proposed development argue that they've left enough open space to make the block a buffer zone even after it is zoned commercial. Besides, university officials say, there's not much left to the residential character of the block. Opponents say the building is too big and too dense to stand on a block that was not supposed to be commercial at all.

Arguments like these are conducted in the language of zoning: acronyms, agency titles, the odd combinations of letters and numbers that determine the eventual sound and feel of city streets. Here is an abbreviated glossary to some of that language.

Zones:

R: Residential. The classifications run from R-1-A (one family detached dwellings) to R-5-D (high density apartment buildings). For example, according to the July 1975 D.C. Zoning Atlas, Shepherd Park is R-1-A to the west of 16th St. and Kalmia Road NW. Apartment-filled stretches of New Hampshire Ave. NW, from Dupont Circle to the Watergate, are R-5-D.

C: Commercial. The lowest, C-1, allows neighborhood stores and restaurants; the highest, C-4, is the downtown business district. Some subcategories allow mixed businesses and residences at various densities. The jumble of restaurantst, groceries, and apartment buildings around 18th St. and Columbia Road NW, for example, is zoned mostly C-2-B, which the city defines as "medium high and high density mixed residential and commercial."

Agencies:

The Zoning Commission: Five members, nominated by the Mayor and confirmed by the City Council. Three are citizens (paid on a per diem basis); one is the Congressionally appointed Architect of the Capitol; one is the director of National Capital Parks, who may appoint an alternate to serve in his or her place. Approves zoning regulations and amendments; sets policy and guidelines for the Board of Zoning Adjustments.

Board of Zoning Adjustments: Five members, three of whom are citizens appointed by the mayor and paid on a per diem basis. One represents the National Capitol Planning Commission and has traditionally been an N.C.P.C staff member. One is a representative of the Zoning Commission. Approves or denies requests for exceptions to the zoning regulation; makes administrative rulings when someone disputes a decision by the Zoning Administrator.

Zoning Administrator: a Civil Service employee of the D.C. Department of Housing and Community Development. Evaluates building proposals for their consistency with zoning regulations; approves or denies permits on that basis.

F.A.R.: Floor Area Ratio, a measurement of building density. A building with an FAR of 1 has floor space equal to the size of its lot; an F.A.R. of 7 means the building's floor space is seven times its lot space. Allowable F.A.R.'s vary according to zoning. City maximum is 10.