For a couple of years now, we of the press, including those of us who know some Russian, and lots of others have been talking of Soviet leader Mikhail Gorbachev's campaign for ''openness'' -- to the point of making glasnost one of those few Russian words that is presumed to be in the informed citizen's vocabulary and so hardly needs to be translated anymore.

It comes, then, as a rude but necessary awakening to be told by former American diplomat William H. Luers, in a footnote to his article on Eastern Europe in Foreign Affairs magazine, that we have got the translation wrong -- and that it makes a heck of a difference, too.

Luers, an old Moscow hand and our ambassador to Czechoslovakia in 1983-86, translates glasnost as ''public airing,'' footnoting as follows:

''One equivalent in Czech to glasnost seems to be hlasitost, which means 'loudness.' The Czechs . . . simply use the Russian word in reporting about Gorbachev's efforts, but they, like others in Eastern Europe, know that it does not mean 'openness,' and speculate that it is closer in meaning to 'publicity.' This is the meaning listed in Russian/English dictionaries. The English-language media and scholars seriously distort its meaning, in my view, by translating glasnost as 'openness.' "

With a clutching feeling, I looked up -- for the first time -- glasnost in my old student Smirnitskii. ''Publicity.'' An unsystematic computer search established that in Gorbachev's first days, Reuter was saying ''publicity'' and the Associated Press ''openness or publicity'' -- evidence that some journalists were trying to grapple with the complexity of it all -- but in more recent times almost all of us have succumbed to the convenience of ''openness.''

What difference does it make? Only this: openness summons up the friendly images of an open Western-type or would-be-Western society, while publicity or public airing, though not exact, indicates more of the truth of the matter, which is the use of information or inquiry by an otherwise closed communist society for purposes that the leadership alone defines.

Practically speaking, openness involves publicity and publicity involves some openness. Essentially, however, openness goes to the nature of a society that is shedding controls, and publicity is merely a technique of manipulation, something subject to being turned on and off.

In political terms, routine usage of "openness" gives an unearned gift to Gorbachev. That term tends to make his policy sound familiar, safe, innocent, incipiently democratic, potentially converging. No single thing may have softened his Western reception more than the uncritical spreading of this one definition of glasnost by the journalists and others who are supposedly the guards at the linguistic/political gates. Carelessness and wishful thinking surely account for some part of this pervasive misreading.

But there is another part, which is that glasnost is an odd duck, and none of us, perhaps not even Gorbachev, has yet figured out exactly what it is. It is not just hopeful Westerners, for instance, who see the new mode as something that could move the Soviet Union toward pluralism and democracy. Wary Soviet communists feel the same way. Princeton's Robert C. Tucker notes that Gorbachev has found it necessary to quash fears that his prescriptions seemed too radical, assuring the Communist Party's central committee that ''no breakup of our political system'' is intended.

Gail W. Lapidus, a Berkeley professor, locates in glasnost a ''simultaneous connotation of both candor and publicity'' whose purposes are to reduce the Soviet people's reliance on foreign (radio) and unofficial (gossip) sources of information and to enhance the regime's credibility and popular standing. Glasnost also offers, she observes, ''a convenient weapon for use against political opponents.''

This element of official hands-on is precisely what fades into the mists of openness. The Economist tried and failed this week to find a one-word substitute. Bill Luers' ''public airing'' has two words and handles a bit awkwardly but goes in the right direction. It's got openness.