LD has become as familiar a form of educationalese as PE and P-TA, but for many professionals working with learning-disabled children, it is a misnomer.

First of all, they say, LD children are not disabled: They can learn, although not always in the traditional format. A more appropriate term is "learning difference."

Second, some special educators believe the most troublesome problem is not in the classroom but in social relations at home and on the playground. LD, therefore, may encompass a broader range of "life difficulties."

Children are diagnosed LD if they show a discrepancy or lag between their overall intelligence and their ability to learn in one or more areas. The label is not applied, according to the official definition, when the "disorders in the understanding or processing of language . . . are caused by mental retardation, emotional disturbance, physical handicap or environmental disadvantage."

While every LD child is unique--ranging from the severely dyslexic child who has difficulty reading, to the restless, inattentive child--there are common traits, says Betty Osman, a New York education therapist and speaker at a Washington conference of the Association for Children and Adults with Learning Disabilities (ACLD).

"Many LD children have problems with understanding, processing or expressing language. This may be the 5-year-old whose speech sounds babyish or the 12-year-old who laughs at a joke five minutes after he's heard the punch line."

"Other LD children have trouble translating information as it is perceived by their senses. Their conversation may sound very bright and intuitive, but they flunk every spelling test, because they have problems sorting out the sounds they hear.

"A third problem area is behavior, including catchwords like impulsivity, short attention span and distractibility. These difficulties are apparent in the child whose voice is often pitched above conversation level and who is a disaster in a classroom where he is expected to sit still and listen."

Each LD child has his own collection of characteristics that may include problems in all three areas. And usually, they become glaringly apparent when he enters the school system.

David, for example, felt overwhelmed by nursery school and tried to escape with frequent trips to the bathroom. When he couldn't escape the 9-to-3 regimen of first grade, his restless wiggling repeatedly landed him out of his seat and onto the floor. His teacher punished him by ordering him to kneel in the aisle.

In the second grade, he got a break with a teacher who provided outlets for his distractibility, such as appointing him "classroom pencil sharpener." And she encouraged him to take time out when he felt jumpy.

On the soccer field, David didn't understand the plays and tried to compensate by rushing feverishly about the field after his teammates, forever too late to kick the ball. At home, he was admonished endlessly by his parents to "calm down."

By the time he had reached the third grade and had received several report cards loaded with D's, David was tested and diagnosed LD. Today, he is repeating the third grade, earning B's and C's and visiting an LD "resource teacher" several times a week.

Just two decades or so ago, children like David would probably have been called "lazy" or, at best, "slow learner" by their teachers, and "dumb" by their classmates.

Yet even with our increased understanding of LD, people still confuse it with mental retardation. In reality, LD children show a full range of IQ capabilities. (Albert Einstein and Thomas Edison had learning difficulties.)

LD is also misunderstood, say special educators, because unlike physical handicaps, it is a "hidden" problem. As a result, people may expect more from LD children than they are able to deliver and criticize them for "just not trying hard enough."

In addition, says Osman, "LD encompasses more than the three R's. If a child doesn't perceive words on a page accurately, he also may misread body language and other subtle communication cues.

"For example, if someone casually asks, 'How are you?' an LD child may launch into a 10-minute monologue, not realizing that a quick 'fine' was all that was expected. Or, in a group of boys who are cutting up, the LD child may be the one who doesn't read the signal that the principal is coming and it is time to stop."

These misperceptions, along with social immaturity and lack of caution, can lead to problems in getting along with peers and become, says Osman, a vicious cycle. If the LD child is rejected for behaving inappropriately, he may become anxious and act out as the class clown or bully, inviting more rejection. Or he may withdraw from his classmates into his own fantasy world. The social difference plus the learning difference often add up to a plummeting self-image.

Jim, 15, whose learning problems began in the third grade, says he turned the tables by "making fun of the other students who could do well in math because I felt bad that I couldn't." "So frustrated" by the time he reached eighth grade, he started skipping classes, taking drugs and stealing.

Jim is typical of LD children who decide they would rather be labeled "bad" than "dumb": LD children are twice as likely to be adjudicated in a juvenile court as are "regular learners," according to a recent five-year ACLD study. Educators, however, are quick to point out that the link between LD and juvenile delinquency does not necessarily mean children with learning difficulties will become delinquent.

Jim has since spent time in detention, a group home and now is reported to be doing well in a residential vocational school with an individualized program for LD teens.

The challenge, say special educators, is to help LD youngsters build on their strengths and compensate for their learning deficits before they feel overwhelmed by defeat.

For Richard, 17, this has meant using a computer in his alternative high school. Troubled with dyslexia for years, he "lost a lot of the thoughts I was trying to get down in the effort of trying to form the words. Now I can type on the computer keyboard and get it all down before I forget it." Richard's enthusiasm has led him to set up his own dealership selling microcomputers after school.

Also dyslexic and the mother of a dyslexic young adult, Ann Mathias, wife of Sen. Charles McC. Mathias (R-Md.), says sheer determination and a supportive family helped her deal with a disability that the schools, at that time, were unable to remediate.

"I couldn't perform the way everyone else could, and I was always wondering, What is the matter with me? And I thought it was unfair that I received a failing grade when 99 percent of my answers were correct, but I didn't have time to complete even half of the test.

"Pretty soon, your willingness to want to continue seems an awful burden. You move from I'll do my best to I can't," says Mathias, board chairman for The Lab School of Washington, a private school for LD children.

Mathias went on to graduate from Vassar College, despite the discouragement of her high-school teachers. "The only way I could know if I could do it was to try. It took me four times as long to do my assignments as everyone else, but I was very stubborn and tenacious."

From her own experience with LD children, Mathias adds, "People who have made it the tough way are some of the most perceptive and determined people I know. They are real survivors."