The abortion issue is back.

After nearly four years of Maryland legislators' generally keeping their distance from that volatile question, it appears that the abortion debate, with all its attendant emotional baggage, will be thrust into the forefront of the up coming General Assembly session.

The tone of the debate may have already have been set by a bill filed last summer by Del. Leo E. Green (D-Prince George's). The legislation, if passed, would prohibit Maryland Gov. Blair Lee III from appropriating state funds to pay for the abortions of women who can't afford the operation.

Oddly enough, it is in the "Definitions" section of the bill, a section usually filled with little more than drab legalistic terminology, that the emotional tone of the legislation comes through most stridently.

"In this section (of state law)," the bill reads, "'abortion' means the intentional destruction of the life of an unborn child, and 'unborn child' means a human being from the time of conception until it is born alive."

"This is going to be some issue, you'd better believe it," said Eileen Hutchinson, the expert an abortion questions in the state's legislative reference department.

At the center of the debate is money: the $1.4 million Maryland has spent annually to pay for the abortions of women in the Medicaid program. In 1976, there were 6,000 such abortions performed in the state.

These factors, combined with the fact that 1978 is an election year, prompise to make debate on the issue particularly sharp, for Maryland, a colony originally settled by Catholics in the 17th century, still boasts a sizeable bloc of Catholic voters, especially in such areas as Baltimore City, Prince George's and southern Maryland.

In one sense, a dress rehearsal of the upcoming debate took place earlier this month, before a joint House Senate committee that was ruling on a technical question - a moot one, at that - concerning the state regulation that governs abortion funding.

The committee hearing was necessitated by a series of events:

First, last spring, a federal prohibition went into effect, cutting off all funds for Medicaid abortions, with a few drastic exceptions, scuh as cases when the mother's life would be endangered by the pregnancy. Thus Maryland's general fund had to sustain the program on its own.

Then last month, Maryland Attorney General Francis B. Burch issued an opinion that the regulation under which the state Department of Health and Mental Hygiene was distributing abortion funds was too vague.

The department should continue its current practices for a short while, the opinion said - but it should tighten its regulation as soon as possible.

At the health department, it was decided that abortion funding under the existing regulation could be continued until June 30.But the department also asked the Joint Administrative Executive and Legislative Review Committee to approve, on an emergency basis, new regulations which would continue the funding for Medicaid abortions.

The health department's attitude - that it would continue the funding for eight months no matter what the committee did - apparently annoyed some legislators. But annoyance was not the dominant issue at the hearing on the department's request. Outrage - on both sides - far outweighed it.

"Two people read the Bible at us - and that doesn't count the people who waved the Bible at us," said F. Carvel Payne, who served on the committee's staff. "Some witnesses cried on the stand.

"There were 17 people signed up to testify for the measure; there were 21 against," he added. The committee voted 7 to 2 not to extend the regulations on an emergency basis.

Now some observers feel that the Nov. 8 hearing gave the issue a highly emotional sendoff, and that the debate in the General Assembly is likely to be extremely fierce. Thirty-eight of the 141 delegates have co-sponsored Green's bill to eliminate funding for most abortions; Lee and Senate President Steny H. Hoyer stand on the other side of the issue.

"It's going to be a close question," said Del. Steven V. Sklar (D-Blatimore City), who agrees with Lee and Hoyer.

"And in an election year the intensity of something likethis is going to be magnified at least twice."