Defying an unofficial but powerful ban within the black Baptist clergy here, the pastor of a leading Washington congregation yesterday ordained a woman to the ministry -- an act which, in the past, has led to ostracism.

In a solemn service, the Rev. Carlton W. Veazey led the ordination of the Rev. Jocelyn Watson Garland -- 20 years after he had baptized her -- in the 1,600-member Zion Baptist Church near the Carter Barron amphitheater.

Veazey was joined by more than a dozen area clergymen in the rite, which he predicted would spell the end to the tradition of an exclusively male clergy in predominantly black Baptist churches here.

There is no church law in black Baptist denominations prohibiting ordination of women. Baptist tradition of congregational autonomy demands that the pastor and deacons of each local church must be the sole authority in determining who is not eligible for ordination.

Up to now, an organization called the Baptist Ministers Conference of Washington, D.C., and Vicinity, which includes about 98 percent of all black Baptist ministers in the area in its membership, has been an insuperable obstacle to women seeking ordination in black churches.

Although the Conference has no official standing in Baptist denominations, it has enforced its views by threat of expulsion of any member who participates in ordaining a women. Eight years ago, the Rev. Joyce McKiethan persuaded her father, pastor of St. John's Baptist church, to ordain her. He and four others who joined in the service immediately were expelled from the Conference.

Since then, black Baptist women who wished to join the ministry have had to compromise by finding other areas of service or joining another denomination.

In discussing his plans for yesterday's service, Veazey said he had considered the possible ostracism he may face, but refused to be influenced by it. "My position is that I try to be cooperative with the brethren and I respect the fellowship, but there are certain things on which each minister must take a stand," he said.

The Rev. J. Terry Wingate of Purity Baptist Church, in speaking to the congregation yesterday, expressed similar views. "We have been told that you are putting your fellowship with other pastors on the line" by participating in the service. "But I don't worry about fellowship with man, because I have a telephone to Him."

Wingate quoted from a document of the American Baptist Churches, the denomination to which Zion belongs, which stated that "whereas Jesus came to bring salvation for all persons . . . women must be empowered to have them do what God would have them do."

The Rev. Dr. Dearing E. King of Chicago noted in his sermon that in a Biblical account of the charge to preach the Gospel, "Luke didn't say anything about permission from the Minister's Conference."

Ordained along with Jocelyn Garland, 30, was her husband, Douglas, 34. The Garlands, who graduated last month from Howard University Divinity School, will become full-time assistant ministers of Zion, working with a new family ministry.

Also ordained yesterday was the Rev. Claudie Grant Jr., a lawyer currently working for the Department of Justice while he completes his work at Howard Divinity School

Veazey said he believes that a large number of his fellow Baptist ministers, "especially the younger men" agree with him on the question of ordaining women. "I think they suffer from peer pressure rather than logic," he said. "If you get them one by one, I think they would agree there's no problem."

The nearly a score of clergy who joined in the actual ordination rite yesterday included a number of Howard faculty as well as the Rev. Jerry A. Moore Jr. of the 19th Street Baptist Church who is a member of the D.C. City Council.

Veazey believes that the prestige of the group will help to convince other Baptist ministers that they should drop their opposition to ordaining women. He said he knows of one other pastor who plans to ordain a woman.