Imagine a holiday that is a blend of Thanksgiving, Christmas, New Year's Eve, the Fourth of July and maybe a little bit of Easter thrown in for good measure.

That comes close to what the Lunar New Year, which starts today, means to the 29,000 Chinese and Vietnamese residents of the Washington area who began preparing weeks ago for the traditional observances.

The holiday, which falls on the first day of the first new moon of the lunar calendar, is a period of great happiness and, above all, stresses the importance of family ties, said Yihyun Hsu, a nuclear engineer from Gaithersburg.

"On New Year's Eve, every member of the family is supposed to go home to have a big dinner together. No matter how far away, you try to get home," said Samuel Peng, a federal employe.

Hsu and Peng talked about the holiday last weekend at the Gaithersburg Junior High School, were Chinese children attend a Saturday school to learn the customs and traditions their eleders brought from the old country. An estimated 6,000 Chinese live in Montgomery County, the largest concentration of the approximately 15,000 Chinese in the metropolitan area, according to Kung-Lee Wang, an Interior Department economist and founder of the Organization of Chinese-Americans.

The new year, which is called Tet by the Vietnamese, can come as early as Jan. 21 and as late as Feb. 19, and festivies continue for two weeks, until the first full moon. This is the Year 4679, 10th in the 12-year lunar cycle, and is the Year of the Rooster.

The holiday began as a midwinter festival to celebrate the completion of the harvest and the beginning of a new agricultural year, and Chinese and Vietnamese, no matter what their religion, celebrate it.

Traditionally, said Hsu, New Year's Eve was a time to settle all debts and to start with a clean record.

"It was a time to start the new year over and start with no qurarles or fighting and no one can ask you for money. Everybody starts the new year as friends. Only, if a guy is really way in the hole, he has to hide," he laughed.

In the weeks of preparations for the holiday, every family member gets new clothes to wear New Year's morning. Houses are specially cleaned and decorated with spring flowers, and special foods are prepared.

Poems painted on red paper are hung on the door and the house is decorated with characters representing "happiness," "luck" and "longevity." Sometimes, the Chinese hang the "happiness" character upside down so that when guests come in they will comment, "Your happiness is upside down," which in Chinese sounds very like they are saying "Happiness is coming," another lucky portent for the new year.

In Vietnamese households, according to Kim-Nga thi Nguyen, who works at the Takoma-East in Silver Spring (TESS) Community Center, families gather, usually in the home of the first son, to spend the first days of the new year together. Welcoming the new year with an abundance of food protends well, so the household must have enough for everyone to eat for three days. The belief is if you don't have enough on New Year's Day, you won't have enough during the year.

In Chinese homes, a family tree is erected with names of all the ancestors listed in sequence. At midnight, as the new year begins, children show their respect for their ancestors by bowing to the family tree and then to their parents.

On New Year's morining, Chinese children often find a red envelope containing money under their pillows, a gift from their parents. When they go to visit adult relatives and bow to honor them, they also receive the red-wrapped gifts of money, called lai-see.

"It's very important to stress your position in the family," Hsu said. "Here the kids are kind of Americanized, but even here I think our kids are more respectful to their elders and eventeachers,"

"Children can really collect a lot," said Peng. "What they do is take the money and go on the street and buy things -- usually firecrackers are real popular."

Vietnamese traditions call for families to awaken and prepare foods which are offered to the ancestors before the family begins to eat, Nga said. This ritual is repeated at every meal for three days as "we pray that our ancestors can come back with us and stay for three days," she said.The family also prays for happiness, health and money.

Both Vietnamese and Chinese prepare a sticky, sweet rice cake to offer visitors on New Year's. In Chinese, the name for rice cake is a homonym for "higher," another sign that the new year will be better than the last. Similarly, it is traditional to serve a dish of fish on New Year's because the Chinese world for fish sounds like the word for surplus, another good omen.

Tet can be a particularly prignant time for Vietnamese, may of whom left family members behind when they came to the United States. It is a time when they can be especially homesick.

"If some people have a family broken up, I ask them to come to my house and use my family," Nga said. "People have been here for four or five years, and it's getting a little easier for them. They are not as homesick as the first year," she said.

For Vietnamese in Montgomery County there will be a special program Saturday evening at Montgomery Blair High School. Nga said children have been studying traditional dances and song and will perform.

She said organizers expect about 1,000 Vietnamese -- half the Silver Spring area's Indochinese population -- to attend. An estimated 14,000 Vietnamese live in the metropolitan area, 4,000 of them in suburban Maryland. v

The Maryland suburban Chinese community also has planned several special events throughout the two-week celebration. A Chinese medical society plans a special banquet dinner Sunday at the Pine and Bamboo Restaurant, Bethesda, and a benefit ball sponsored by the Rho Psi Society is scheduled for 6:30 p.m. Feb. 15 at the Sheraton Potomac Inn, Rockville. Proceeds will be used for awards for three students who exhibit leadership in community affairs.

Although the biggest celebration of the year for Chinese, said Kung-Lee Wang, most workers will be on their regualr jobs and businesses will be open. He said children will attend public schools as usual, and parents will not take the day off.

"Some people have been raising the question that Jewish people do get religious holidays but Chinese people don't get any religious holidays. If they should have anything for the Chinese American, this would be the one."