Frederick B. Senior is a 42-year-old Kappa. His college memories, his closet friends and now even his son are tied to the black Greek fraternity, Kappa Alpha Psi, which he pledged in the mid-'50s.

Senior, special assistant to the director for management information systems at the D.C. Department of Human Resources, vividly remembers when segregation precluded blacks from participating in white social activites in Washington. His fraternity's midnight "Easter Dawn" dance was one of the black social highlights of the year, Senior recalled.

Now, more than 20 years later, Kappa Alpha Psi plays a different role in Senior's life. While it remains a vehicle for social activities, it also permits him to help others in the community. Senior takes part in a number of the fraternity's civic activities directed toward senior citizens and youth.

Senior is among more than 20,000 blacks in the Washington area who are members of eight fraternities and sororities, which have more than 20 college and alumni chapters throughout the Washington area.

The alumni chapters of the Greek organizations offer scholarships to local youth, given aid in reading, provide donations to the NAACP and the United Negro College Fund and offer guidance to their own college chapter members. Some chapters have obtained various federal and private grants for their projects.

Members of local black fraternities and sororities, a number of which were organized at Howard University at the turn of the century, believe that there is a sharp contrast between their groups and traditional white Greek organizations. They cite a major difference in the economic status of black and white students and alumni, the lack of an "old boy" network to help black graduates obtain jobs and their special interest in minority community activities.

Wiley Branton, dean of Howard's law school and an alumnus of Omega Psi Phi, said: "When you compare white to black fraternities, you are talking about two different animals."

Branton explained that black fraternities have to be more than social organizations. He said black fraternities, in contrast to their white counterparts, are not financed by wealthy alumni. He said black fraternal organizations have to use limited resources and "assume a special kind of importance in the black community."

Many of the black Greek organizations were spawned at black colleges in the era of segregation. The organizations not only provided an alternative to white social life for blacks, but often provided off-campus housing for out-of-state fraternity members and their families.

Membership in black Greek organizations includes mayors, judges, lawyers, doctors and college presidents as well as "African kings."

In Washington, for instance, Mayor Walter Washington is a "Q," or a member of Omega Psi Phi. His wife, Bennetta, is a member of Alpha Kappa Alpha. D.C. Delegate Walter E. Fauntroy is an "Alpha," or a member of Alpha Phi Alpha. So are Marion Barry, Sterling Tucker and Supreme Court Justice Thurgood Marshall. Joseph Yeldell, former director of the Department of Human Resources, is a Phi Beta Segma as are B. Doyle Mitchell, president of Industrial Bank, and retired Associate Judge Hubert B. Pair of the D.C. Court of Appeals. Julian Dugas, city administrator, is a Kappa, as is Winfred R. Mundle, general counsel for the D.C. Board of Elections and Ethics.

Patricia Harris, secretary of the federal Department of Housing and Urban Development, is a Delta Sigma Theta. So is Rep. Barbara Jordan (D.-Tex.), Flaxie Pinkett, D.C. real estate and insurance executive, and singer Roberta Flack. The list includes many top professionals, athletes and government employees.

For many years, the organizations served as social stepladders for working-class blacks to ascend to middle-class status. "Conspicuous consumption" became a way of life for some members of the Greek organizations, and lightness of skin color and grade of hair were often important tests of success in the middle class.

E. Franklin Frazier in his book "Black Bourgeoisie: The Rise of a New Middle Class," written during the 1950s, said fraternal groups provided the main expressions of "social snobbishness" on the part of the black bourgeoisie. He also said, however, that next to the church, "the various fraternal organizations have represented the most influential associations which (blacks) have built up within their segregated social life."

The black fraternal organizations Frazier wrote about more than 20 years ago have undergone dramatic changes, according to current members. The fraternal organizations no longer emphasize color, they no longer provide the primary social outlets for blacks and they no longer represent the high level of social status of the past.

One of the key reasons, according to members, was the black power movement. Black power advocates called the members of the black Greek organizations "bourgeoisie," a term for snobbishness in the black community. They said the fraternal groups divided the black community into "nonrelevant cliques." As a result, the membership of many black Greek organizations dramatically tapered off during the late 1960s, according to Gerald Smith, a national officer and historian for Phi Beta Sigma Fraternity.

According to Smith, chapters literally disappeared from many of the college campuses across the country. One Howard University administrator said: "For several years you couldn't tell there were Greeks on campus."

Now, although membership is again on the rise, according to black Greeks, there is pressure internally and externally for the organizations to increase their civic involvement.The degree of civic involvement still remains a key issue, however, for some critics who still contend that the groups are primarily middle-class social organizations.

Senior, the "polemarch" or president of the Washington Alumni Chapter for the Kappas, said his chapter provides a number of civic services, including providing transportation to senior citizens at Edgewood Terrace Apartments twice a month for shopping and offering activities and counseling for local youth. He said he hopes his chapter will reach more people this year.

Senior said his chapter has 220 active members, making it the largest Kappa alumni chapter in the country. He calls it "flagship of the Kappa alumni chapters."

Senior said his son has also joined a Kappa chapter in the South. He added that it is not necessary to pledge a college chapter in order to join the alumni chapters. In some fraternities, it is more difficult to join alumni chapter without first pledging a college chapter.

Civic activity is important to both the alumni and college chapters. These chapters take particular pride in the dollar amounts they donate to other national black organizations as well as programs they participate in themselves.

Marjorie A. Kinard, president of the Delta Sigma Theta Washington Alumni Chapter, said her national organization has produced a motion picture and a record album as well as receiving a grant to encourage blacks to watch public television. In addition, her chapter has sponsored several seminars dealing with university and college preparation and with encouraging home ownership. Members also have taken black teen-agers to various agencies to acquaint them with a wide field of jobs.

Lillie J. Vanlandingham, "basileus," or president, of the Washington alumni chapter of Sigma Gamma Rho Sorority Inc., which began at a teacher's college in the Midwest and still has a large teacher membership, said her organization works with senior citizens at the Phyllis Wheatley YWCA on Rhode Island Avenue and conducts a special education program for teen-age mothers.

"We all take a different approach, but we all know where we are going," said Harriet Harper, basileus of the Alpha Phi Alpha alumni chapter, which has 250 active members.

Her chapter, which was founded in 1908 at Howard, is involved in a reading project at McFarland Junior High School as well as in national projects.

She said many of the Greek organizations are "getting into larger projects and getting funding they've never gotten before."

One black Greek fraternity, Omega Psi Phi, sponsored a housing project in Northeast Washington, and each of the other organizations has national projects that are affiliated with other organizations such as the March of Dimes.

Elmer J. Moore, president of Mu Lambda, the Washington graduate chapter of Alpha Phi Alpha, said his organization - like the others - is sponsoring a number of scholarships to local youth.

Although Mu Lambda is involved in civic projects, the organization's "special focus" this year, Moore said, is preparing for the 1979 national convention tobe held in August at the Washington Hilton. "We are setting up various types of committees that will take care of various activities, entertainment, golf, tennis, bridge tournaments, dances and sightseeing activities," Moore said.

Not all alumni are happy with the activities of their organizations. An alumni Alpha Kappa Alpha sorority member, who asked not to be identified because "Everyone knows me," complained that she is"frustrated with the organization."

"I go to the meetings and all they talk about is fashion shows. I like fashion shows, but now they are costing $15 and $16 and that is too much. I think they should be more serious . . . . They should be into lobbying on the Hill and things like that, not just this social stuff."

She said she plans to let her membership expire.

Marion Barry said through a spokeswoman that he became an Alpha in his sophomore year at LeMoyne-Owen College in Memphis. He said he now is considering becoming active in the local alumni chapter.

According to Barry, "The fraternity has certainly been an influence in my life . . . . I joined when I was a sophomore because it was the thing to do. It brought people together around the ideals and programs of the fraternity. Those of use who came through at the same time are still very close."

Mayor Washington, according to his wife Bennetta, was the president of the Omega Psi Phi chapter at Howard in the early 1940s. She said the mayor is still a "financial member of the organization," but he has not taken an active role because as mayor he has had to deal with all fraternal organizations.

When asked if she was a member of a sorority she responded: "Absolutely, of course I am!

"These groups went beyond the social partying. That was what attracted you to them. There was camaraderie, that kind of personal concern that brought people together on issues."