Our society puts labels on things. It warns us of danger: cigarettes can kill you; beware of poisons and spinning blades; don't step on the top rung of a ladder. They educate us: a candy bar contains 300 calories, a shirt is all cotton or all silk, a car gets 20 miles to the gallon. We mandate and regulate labels with laws and government agencies. "Truth" in labeling is the ideal we seek.

Newspapers are in the labeling business too. Our labels are not regulated by the FTC or the Consumer Product Safety Commission. They need not be "true," accurate or even useful. But we have an inexhaustible supply of them to hang, as we choose, on people, institutions, nations and things. We use them to simplify complexities: "Cold War," "Iron Curtain," "Free World." They enable us to classify and pigeonhole humanity: "blue collar," "white collar," "hard hat," "yuppie," "rich," "poor," "black," "white."

"We categorize people," Robert Coles wrote 20 years ago, "and call them names like 'culturally disadvantaged' or 'white racists,' names that say something all right, but not enough -- because those declared 'culturally disadvantaged' so often are at the same time shrewd, sensitive and in possession of their own culture, their own way of giving order to this world's complexities, just as those called 'white racists' have other sides to themselves, can be generous and decent, can take note of and be responsive to the black man's situation."

In Israel last week, an Egyptian ambushed military and civilian cars and buses, killing four people and wounding 26. Was he a "terrorist"? A "freedom fighter"? A "fanatic"? He may have been all three. He may have been insane. The Israeli police don't know. Jackson Diehl, The Post's correspondent in Jerusalem, didn't know. So he described the man as a "gunman," an "Egyptian," an "assailant."

That was unsatisfactory to some readers. They hung a label on The Post -- "anti-Israel" -- for failing to label the gunman a "terrorist." I'm sympathetic to those critics, because we are often not as rational and disinterested as Mr. Diehl in labeling the subjects of our stories. Instead, it is frequently the case that the labels we use are more descriptive of our own states of mind -- expressions of approval or disapproval -- than descriptive of the individuals or acts we hang them on.

What is a "terrorist" act, and who is a "terrorist"? Was the truck driver who blew up the Marine barracks in Lebanon in 1983 a "terrorist" or a "Moslem warrior" in the army of Hezbollah? Is it "terrorism," "self-defense" or "pacification" when Israeli soldiers kill civilians, destroy homes, orchards and crops in the occupied West Bank? Is it "war," "terrorism" or something else when the armies of Beirut conduct lethal operations in residential neighborhoods, shopping districts and hospital zones, murdering countless women and children in the process?

We have trouble with those labels, and there is substantial confusion among us over useful definitions of the words themselves.

There are other profound confusions. How are we to comprehend what the journalist in Moscow or Eastern Europe is trying to say when he labels the Communist of 1990 a "conservative" or "right-winger" and the free market capitalist a "reformer," "radical" or "leftist"? Are these definitions and labels transferable to this hemisphere, instantly transforming Castro into a "reactionary," the U.S. Communist Party into a "right-wing" front and Ronald Reagan -- perhaps more popular in Moscow today than in Washington -- into a new "leftist"? For that matter, here at home, are there any distinctions between the "conservative" and "right-wing" schools of American thought or between "liberal" and "left-wing" orthodoxies?

I am sure there are answers to such questions. I am also sure you are not likely to find them in the "media." In fact, it is probably the case that most politicians are as incapable as most journalists of providing coherent definitions for the labels that pour daily from their mouths and from our word-processing machines. Ours is a dialogue of cliches.

It would be helpful to "media" consumers if we, myself included, occasionally would think about our labeling practices. They are not likely to change; too much habit and convenience are involved. But as writers and readers we can, at the least, try to remember that a label is merely a label; it is not the real thing.