A story in yesterday's Washington Post contained a typographical error saying 9 million Palestinians live in Jordan.Actually, about 1 million is the generally accepted estimate.

"Ai qadhieh al-Filestinieh" -- the Palestinian cause -- has become for most of the Arab world what "Remember the Alamo" was for a generation of Americans, a rallying cry and common denominator in a complicated formula of brotherhood, national interest and wounded pride.

Four major Middle East wars and countless skirmishes have been fought in the name of the Palestinians. Even now, most opposition to the U.S.-sponsored peace treaty between Israel and Egypt springs from a feeling that the "cause" has been sold short.

Arab concern for the fate of appoximately 3 million Palestinians outside Israel rises in part from humanitarian considerations -- the spectacle of Arab brothers pushed from their homeland into refugee camps or lives as stateless immigrants whose future often hangs on a visa.

But it also rises from the feeling, widely shared across the Arab world, that the Palestinians' struggle against Israel is also all Arabs' struggle against Israel.

Historically. it has been. Egyptian Syrian and Jordanian armies have done most of the fighting, with Palestinians themselves playing only minor roles. The battles of these armies have broadened into the battles of the Arab world, bound together by common language, culture and history. Even the Lebanese, bystanders in the struggle and resentful of the Palestinians in their country, wept in the streets when Jerusalem fell to Israel in 1967.

"The military defeat, the humiliation, the moral outrage are felt by Arabs to varying degrees all over," said Hisham Sharabi, head of the National Association of Arab Americans, professor of Arab studies at Georgetown University and himself a Palestinian active in promoting the "cause."

The sense of Arab community is reinforced by Islam, the religion of most Arabs and the major source of their culture. But Islam is only part of the Palestinians' claim on the Arab world. The substantial Christian Palestinian minority has done nothing to weaken it.

The Palestinians' moral hold on the Arab world did slip, however, during the massive Palestinian participation in the Lebanese war providing a bitter lesson to the Palestine Liberation Organization leadership of Yasser Arafat.

The Arab world had cried indignantly -- and Syria even dispatched a tank column -- during the Palestinians' war against King Hussein of Jordan in 1970. But it stood by idly six years later as Syria's President Hafez Assad sent his Soviet-supplied tanks to blast away Palestinian forces frustrating his policies in Lebanon.

To some observers, Arafat's largescale involvement in the Lebanese conflict marked an important turning point in Arab support for the Palestinians. Afterward -- and after Assad crushed Palestinian resistance -- it no longer seemed sinful for Arab leaders to make it known that they would accept the West Bank and Gaza for the Palestinian state that is the chief element of the "cause." Previously, any willingness to accept such a solution was carefully concealed or at least hedged in public policy statements.

The guerrillas' role in Lebanon is the most dramatic illustration, and the bloodiest, of the influence of Palestinian presence in the Arab world. An estimated 400,000 Palestinians have been forced to make Lebanon their temporary home, and the sunny Mediterranean country probably will never be the same because of it.

Palestinians have left their mark on other Arab countries as well. Aside from the half million in Israel proper and the 1.1 million in the occupied West Bank and Gaza, Palestinian refugees, in camps and out, are scattered about the region:

-- Syria has 250,000.

-- Jordan has more than 9 million.

-- Saudi Arabia has 50,000.

-- Kuwait has 250,000.

-- The other Persian Gulf states, Europe and the United States have another 250,000.

"We are living with them, their problem, their tragedy, every day," explained Syria's ambassador to the United States, Sabah Kabbani. "You feel it; you see it."

Palestinians do more, however, than prick Arab sympathy by their simple presence. Many hold key positions in commerce, government bureaucracies, education and the press. A fiery editorial in a Kuwaiti newspaper supporting the Palestinian cause, for example, often reflects the passions of a Palestinian editorial writer more than the opinions of a Kuwaiti newspaper owner.

With their numbers, their energy and their high level of education, Palestinians make up a troublesome factor in the populations of Arab countries that receive them. Absorption -- even if Palestinians would accept it -- has been made difficult by Arab League decisions refusing naturalization to the refugees.

As a result, many Arab leaders yearn for a Palestinian state as much to get rid of a potential troublemakers as to secure justice for the Palestinian people.

The confusion in some Palestinian guerrilla groups between "the cause" and leftist ideology also makes the rulers of conservative Arab states nervous, and all the more eager to give the Palestinians a home of their own.

"Unless [the Palestinians] are brought into the community of nations, they will continue to be a disruptive element," said a U.S. official closely concerned with the problem. "And these people known that."

Oddly, however, some of the most unconditional Palestinian support comes from nations without any significant Palestinian refugee population -- from Iraq, Libya and Algeria. These states have identified the Palestinian struggle with their own policies against Western influence in the Middle East.

Throughout the Arab world, but particularly in these radically Pan-Arab states, Israel is seen as a foreigh injuction of European civilization into the Middle East and backing the "cause" becomes an extension of Arab self-assertion against former colonial influence.