What was going on when I was born?

The Trans World Corporation, in a five-hour directors' meeting in San Francisco yesterday, approved plans to spin off its Trans World Airlines subsidiary as a separate company. The company said no details of the board's action would be available until today. But based on tentative outlines of the proposal, stockholders would receive 93 shares in the airline for each 100 shares of common stock they now hold in the parent company. The spinoff - which will require shareholder approval at a meeting in December - was viewed as Trans World's response to an unsuccessful proxy fight by Odyssey Partners last summer to dismember the company.

The first Americans to be evacuated from Grenada since the United States invasion arrived here this evening. Some knelt and kissed the ground after they stepped from an Air Force C-141 transport plane and others whooped to express their pleasure to be home. ''I don't think there's any more beautiful sight than the United States,'' said Jean Joel of Albany, N.Y. ''And the rangers who arrived to save us.'' She was one of 69 Americans and two Britons, all of them students at St. George's University School of Medicine, who arrived on the first plane to bring people off the tiny Caribbean island since American marines and soldiers invaded Tuesday.

AnAppraisal NEW HAVEN, Oct. 24 - Long ago, the British magazine Punch called the undergraduate colleges of Yale ''a stage set made in Hollywood for a musical about Oxford,'' and it was partly right. Yale's 12 colleges were conceived as buildings that would remind their occupants of someplace else. But if these buildings were inspired by a yearning to be elsewhere, after half a century the colleges have come to symbolize New Haven far more than Oxford or Cambridge. It says much about the quality of the architecture of this campus that today these buildings call to mind not medieval universities at all, but Yale itself. The division of Yale 50 years ago into a system of undergraduate residential colleges, each with its own master, dean and dining hall, was intended as a means of breaking down the scale of the university, even then growing too large for easy social contact.

The invasion of Grenada is advancing ''extremely well'' and only one major area of resistance remains, Defense Secretary Caspar W. Weinberger said. He said that American losses stood at six killed, eight missing and 33 wounded. Mr. Weinberger said he was unable to provide any casualty figures for Grenadian and Cuban forces and had no word of any civilian casualties. He reported, however, that about 600 Cubans had been captured. (Page A1, Column 6.) Cuban resistance in Grenada reportedly ended, but American troops battled Grenadian soldiers and militiamen in crowded areas of the capital. The United States flew in hundreds of paratroopers to bolster the force of 1,900 marines and Army Rangers that invaded the island early Tuesday with soldiers from seven Caribbean island countries. (A1:5.)

Quotation of the Day ''We got a lot more resistance than we expected.'' - Gen. John W. Vessey Jr. (A23:1.)

For Nynex, the holding company that will join the New York and New England telephone companies on Jan. 1, its customers are both the problem and the opportunity. Delbert C. Staley, Nynex's chairman and chief executive officer, not surprisingly calls his seven-state Northeast region, with its 30 million people and 10 million customers, a ''big plus.'' As he sees them, the region's strengths include its economic stability, its higher-than-average income base and the many businesses ''involved in the information age,'' which thus makes them heavy users of telecommunications services. ''Despite all you have heard from the Sun Belt states, the sun really does rise over the Northeastern states every day,'' Mr. Staley says wryly. The minuses, however, are compelling, too. They include the region's high costs of doing business, the absence of population growth, its older- than-average telephone plant and its dense population, which fosters economies of scale but also makes it easy for competitors to pick off customers. At New York Telephone, 25 percent of revenue comes from only 1 percent of the company's business customers. Nynex officials acknowledge the vulnerability of their business base.

News session excerpts, page A18. By B. DRUMMOND AYRES Jr. WASHINGTON, Oct. 26 - Secretary of Defense Caspar W. Weinberger said today that the United States military invasion of the Caribbean island of Grenada was progressing ''extremely well'' and that only one major area of resistance remained. Mr. Weinberger said that United States casualties, as of 5 P.M. today, stood at six killed, eight missing and 33 wounded. He said he was unable to provide any figures for combat deaths among the Grenadian and Cuban forces and had no information of civilian casualties or casualties among the 300 troops of the seven Caribbean nations allied with the United States in the invasion.

Allied agencies reportedly have leads suggesting Iranian involvement in the bombings. Page A8. WASHINGTON, Oct. 26 - A senior Reagan Administration official indicated today that at least some marines in Lebanon would be redeployed from Beirut airport to safer places. The official, who is central to the policy-making process, said that the marines were in Lebanon to give confidence to the Government of President Amin Gemayel, but that this could be done from an ''expanded secure zone'' with more room for maneuver. He reiterated that the number of marines would not be increased nor their mission expanded.

Cuban resistance on Grenada reportedly ended today, but United States troops battled Grenadian soldiers and militiamen in congested neighborhoods of the capital. The United States flew in hundreds of paratroopers to bolster the force of marines and Army Rangers that began an invasion of the island early Tuesday along with some soldiers from Caribbean island countries. As the fighting continued, a planeload of 69 American medical school students was flown out to South Carolina. More students at the St. George's University School of Medicine, where 500 Americans have been enrolled, were expected to leave later. There are about 1,000 Americans on the island.

State Comptroller Gerald A. Lewis today ordered 32 telephone solicitation companies based in Florida to stop soliciting investors to participate in a Federal lottery for oil and gas leases. He said they had ''defrauded thousands of investors across the country of millions of dollars.'' Mr. Lewis joined officials of other states who have urged President Reagan to reform the oil and gas lottery program. The Reagan Administration suspended the lottery system earlier this month, but the suspension comes up for review in November.

Companies Chrysler earned $100.2 million in the third quarter, 10 times more than a year ago. The company, which had a 13.8 percent increase in sales, said about half its profit came from tax-loss carryforwards. It also said it might revalue its holding of 1.8 million shares of stock in the French auto maker Peugeot. (Page D1.) More oil companies showed improved third-quarter earnings as a result of cost-cutting programs and higher earnings from foreign operations. Among those reporting, Mobil was up 42.3 percent, Texaco 9.2 percent, Gulf 73.6 percent and Shell 1.6 percent. Occidental's net rose six-fold. (D1.)

For a long time, at the level of Presidential commissions on aging and at university seminars, there has been talk of finding some way to moderate the shock of retirement; to prepare people so that they do not abruptly, in old age, face a void where work has always been. ''It's been talked about for 20 years,'' says Robert H. Binstock, director of the Policy Center on Aging at Brandeis University. In 1978 Congress raised the mandatory retirement age from 65 to 70, allowing people to work on if they chose. But the talk of finding some way to ease the act of retirement itself has remained largely just that, Professor Binstock says - talk. There is one notable exception. In 1977 a new policy emerged at the Polaroid Corporation here. It came not from a board meeting or a company review but from a memorandum issued by Joseph S. Perkins, a 54-year-old mechanical engineer who had been appointed corporate retirement manager.