Would you believe, the use of the name Metro for a rail transit system such as ours in Washington has touched off a minor international controversy?

The man who kicked off the dispute is Prof. Walter Michinton of the Department of Economic History at Britain's University of Exeter. The professor stated his views in a letter to Mass Transit, a Washington-based trade publication edited by C. Carroll Carter. Michinton was troubled by the magazine's latest annual rundown on "subways of the world," some of which, alas, are not subterranean.

" . . . While it was all right to use the word 'metro' for a variety of forms of urban rapid transport," Michinton contended, "it was not proper to use the term 'subway' for lines which were not underground . . . . "

Which leaves us -- and our counterparts in San Francisco and even in New York, where many underground rail lines emerge above ground -- in a kind of limbo. Not all metros are subways; not all subways are Metro, with a capital or even a small M. When we get onto a Red Line train underground at Farragut North, we're on a subway train; when we get off above ground at Shady Grove, we're on a metro -- though we've been on the Metro all the while.

Mass Transit, in an editor's note, told the professor that it had grappled with the description and decided that it would stick to the word subway despite the ambiguities. "Like the industry we report," it said, "frames of reference and definitions are becoming increasingly challenged to meet new demands."

Metro, by the way, is defined in Funk & Wagnall's New Comprehensive International Dictionary -- capital M or not -- as, "In European cities, an underground railway; subway." It derives from the name of the private corporation that once ran one of two rival Paris subway systems: le Metropolitain.

The late Maj. Gen. Jackson Graham, Metro's founding general manager, adopted the name that already was in use not only in Paris but also in Montreal, Mexico City, Moscow and Sao Paulo, Brazil, among other places. It's since been appropriated for the Baltimore subway and the Miami elevated.

But we may be the only place with a Metrobus. A Fuelish Lesson

A friend viewed the benefits of competition the other evening, but too late to take advantage of it.

She dropped by her Arlington neighborhood service station -- one without nearby competitors -- to fill her car's tank with unleaded gasoline at $1.06 a gallon. Then she drove to Alexandria and down North Washington Street, where four service stations compete within two blocks. Unleaded gasoline of the same brand she had bought in Arlington was selling for 96 cents a gallon. Signing Off

Two signs:

* Panels on both sides of truck No. 32 of the Acme Fire Extinguisher Co. proclaim that the firm sells "Industrial Safty Equipment."

* In Rothschild's cafeteria on 15th Street NW, the outsized breakfast menu on the wall asserts: "All eggs made to order." Okay, even if they have a henhouse on the premises, what language do they use to place orders with the birds?