The Wall Street takeover game has shaken off the October stock market collapse and is moving back into high gear.

Yesterday alone, mergers and takeover offers totaling more than $12 billion were announced. In what is potentially the largest, Federated Department Stores said late last night that it has received a $6.6 billion offer from R.H. Macy & Co., the New York retailer, even though it was close to a final agreement to be taken over by a Canadian company for $6.1 billion.

The stock market, propelled in part by the takeover offers, leaped ahead. The Dow Jones industrial average rose 48.41 points, closing at 2071.62, its highest level since the October collapse. {Related stories on Page C1.}

"We are seeing, if anything, more deals than before the October crash," said Martin H. Dubilier, chairman of Clayton & Dubilier Inc., a private investment firm in New York. "We were seeing one deal a week several months ago. Now we're seeing two a day."

Dubilier and other analysts added that the headline-grabbing megamergers of public companies are just a fraction of the actual activity.

"It's booming. I've never seen it in this kind of accelerated fashion," said Larry Wachtel, an analyst at Prudential-Bache Securities. "And beyond the big guys there are many, many deals you don't hear much about."

Foreign money is a major factor in the surge. The decline of the dollar has made U.S. stocks and other property in this country much cheaper for Japanese and European investors.

At the same time, the pickup in deals is itself generating deals. "Guys are scared because they're afraid they are going to be raided because the pieces {of their companies} are worth more than the whole," said Dubilier. This is spurring them to divest unrelated business lines and focus on their core businesses, he said.

In yesterday's action:

Stop & Shop Cos. Inc. of Boston, owner of supermarkets and the Bradlees department store chain, said it had agreed to a $1.2 billion ($44 a share) leveraged buyout offer from a group led by New York investment firm Kohlberg Kravis Roberts & Co. The deal appears to thwart a $1 billion takeover offer from Stop & Shop by Washington's Haft family. The Hafts said yesterday, however, that they will continue to press their $37-a-share offer and their effort to oust the Stop & Shop board.

Cincinnati-based Federated, which appeared last week to have an agreement to be taken over by Campeau Corp. for $6.1 billion ($68 a share), said it had received a new offer from R.H. Macy & Co. for $6.6 billion ($73.80 a share). Directors of Federated -- which owns such department store chains as Bloomingdale's and Burdine's -- were considering both offers yesterday.

Two companies controlled by television producer Burt Sugarman proposed a $1.75 billion ($61.50 a share) takeover of Media General Inc., a Richmond media conglomerate whose holdings include the Richmond Times-Dispatch and News Leader. The Bryan family, which controls Media General, said it wasn't interested in selling.

T. Boone Pickens Jr., a Texas oilman and veteran corporate raider, offered $1.9 billion ($20 a share) for Homestake Mining Co., a gold mining concern in San Francisco. Pickens, who has failed profitably in several major takeover attempts of oil or mining companies in recent years, already owns or controls about 3 percent of Homestake, which said it would study the offer.

Directors of Dr Pepper Co. and Seven-Up Co. tentatively agreed to merge the privately held soft-drink companies. Both companies were acquired in 1986 by separate investment groups organized by Hicks & Haas, a Dallas investment firm, and have become increasingly integrated in the past two years. No terms of the planned merger were disclosed.

Appliance maker Whirlpool Corp. announced plans to acquire Roper Corp. of Augusta, Ga., a maker of stoves and lawn equipment, for $350 million ($37.50 a share).

The deal-making has been made easier, Dubilier said, by a general easing of the fears created by the market collapse. Declining interest rates have made it easier for for companies to finance takeovers. A few months ago, he said, his firm floated such an issue at 15 1/2 percent; today he can find buyers at 13 1/2 percent.

Wachtel said there is pressure from what he called "a narrow political window to get deals done" before the end of the Reagan administration, when regulation may tighten.