Thanksgiving, the one day in the year when most Americans can be equal at the dinner table, was no exception yesterday in the nation's capital as many people who usually have to scratch for their food enjoyed the same lavish repast as those accustomed to eating what they will.

All over town, churches, charity organizations and community centers welcomed hundreds of down-and-outers, disabled persons, elderly persons and some just plain lonely persons to share traditional turkey and trimmings in the the annual rite of generosity, gratitude and gluttony.

In Lafayette Square, activists from the Community for Creative Non-Violence dished out steaming turkey dinners to about 150 street people and put up a tent city, dubbed "Reaganville," in an effort to dramatize the needs of the poor. U.S. Park Police permitted the group to serve food and pitch the tents and said they would be allowed to remain in the square at least until daybreak today.

Many city families spent part of the sunny 50-degree day before television sets watching for a glimpse of the 210-member Shaw Junior High School Band, the first junior high band to march in the annual Gimbels Thanksgiving Day Parade in Philadelphia, now in its 62d year.

The Council of Churches of Greater Washington, in a first-time effort, sponsored more than 1,000 "Walk-in-and-Eat" dinners at 14 locations "because this year there were so many cutbacks in food stamps and AFDC welfare and job terminations," according to the Rev. Ernest R. Gibson, council executive director.

Some had their meal as early as 10:30 a.m., like those at the Sisters of Charity Mission, 3310 Wheeler Road SE, Mother Teresa's mission in Anacostia. Men, many of whom are unemployed, neighborhood children and elderly women sat down to slabs of roast turkey, great hunks of candied yams and slices of pumpkin pie on plastic-draped tables.

Men leaned over their heaping plates as the nuns prayed thanks and led the children in hymns to the accompaniment of Sister Donata's guitar.

"This is what Thanksgiving is all about," said lawyer Ed Bou, chef for the feast donated by the Rev. William Wendt and his St. Francis Center, "although you have some difficulty with the stark contrast: today the gluttony and tomorrow the meager existence. I wish in a way there could be more spiritual input to the meal."

Across town, the House of Imagene was jumping. Loud laughter and good spirits flowed in a narrow row house at 214 P St. NW that doubles as a shelter for battered spouses and home of the Rev. Imagene Stewart, pastor of the Church of What's Happening Now. Flimsy paper plates stacked with food were passed steadily from the kitchen. Paper cups were frequently refilled from a bottle of Bella Vino wine and a bowl of red punch on a table.

Men in three-piece suits, Stewart's fellow employes at the Government Printing Office nearby, mingled with social workers, students and homeless men in ill-fitting coats, as well as Stewart's son, Air Force Sgt. Michael Johnson, 24.

"I ain't doing this because of no bleeding heart," Stewart declared. "I used to be homeless. I used to sleep night after night in Lincoln Park on Capitol Hill, and I asked the Lord if he would help me, I would do the same for others."

"I haven't eaten anything for a week," said Bob Cornell, a 30-year Navy veteran stranded here last Monday when his car broke down on the way from Atlantic City to Pensacola, Fla. He said he'd slept in the car, then on the street and hadn't counted on Thanksgiving dinner until police directed him to the House of Imagene.

At the Masonic Temple at 10th and U streets NW, tables for 100 were set with white table cloths in the huge banquet room. Prince Hall Masons had donated the dinners.

Audrey Rowe, social services commissioner for the city's Department of Human Services, went around the hall wiping up spills and ushering in mothers and children from the Parkside Hotel, the city's shelter for homeless families, and destitute men bused from the old Blair and Pierce Schools, the city's shelters for homeless men.

Gibson said the Council of Churches, has in the past left Thanksgiving efforts up to individual churches but this year sponsored the cooperative charity because "we had gotten word of so much hunger in the community . . . " and because of the "extraordinary psychological impact brought on by our economy.

"Today, Thanksgiving, may be the first direct and undeniable impact of the change in life styles we will have to make because of economic conditions ," Gibson said. "More important than feeding the hungry, we are saying to the metropolitan community, 'Somebody cares.' "