This is the current legal definition.
Definition: A 'learning disability' is a disorder in one or more of the basic psychological processes involved in understanding and using language spoken or written which may manifest itself in an imperfect ability to listen, think, speak, read, spell, or do mathematical calculations.
LD (Learning Disability), and SLD (Specific Learning Disability) are the current terms for people who learn differently.
Dyslexia (reading disability), Dysgraphic (writing disability), and Dyscalculia (math disability) along with a lot of other "disabilities" are all considered a 'learning disability".
ADHD (attention deficit hyperactivity disorder) is not considered a learning disability.
This condition is also referred to as ADD and AD/HD. It is defined as inattention and heightened activity level. When learning is affected, they may also be said to have a learning disability.
Here are some sites with information on "learning Disabilities". As a person who had difficulty learning to read, with spelling, with math, with following verbal instructions, and remembering data, I strongly disagree with the negative attitude of most of these sites. This is because of my experience. I am myself a person with "learning disabilities", have raised a child with "learning disabilities", and successfully tutored children with "learning disabilities" for 40 years.
In high school, I was counseled that since I was incapable of handling college material, I should instead become a decorator. I flunked the ACT test in math and was told that I couldn't go to college. Since I had straight A's at my junior college, they decided to give me a try. Two years later, I graduated with honors from a prestigious private college with an Elementary Teaching Credential.
Since then, I have become a newspaper editor, business manager, magazine writer, technical writer, blog writer, creative writing teacher, and a very successful tutor for children who are struggling in school.
Have I been cured? Of course not! I am still me. I am still a very strong global learner (right-brained). I still have trouble with all the detailed left-brained activities such math, spelling, verbal instructions, phonetic reading, and reading out loud. I can help children with "learning disabilities" because most of them are also global learners (also called visual spatial learners).
I teach these children how I learn, not how detail-oriented people learn. I simply encourage them to develop their abilities; I share my experiences, and confirm to them that they are are NOT "wired wrong". I show them how to cope with details by using technological tools, such as computers, calculators, and spell-check. I teach spelling and math principles and reading globally (ideas to details and sight words). I encourage reading at their interest level, not their verbal reading level (I know this isn't how it is done, but it works!) If they understand what is on the page, that is all that matters.
I'm afraid that I would still be in school remediation if they had Resource when I was in elementary school. Instead, I proceeded on happily not being aware that I was "disabled". I taught myself, and I learned to use my global writing abilities to compensate for my inability to remember specific details. For example, my high school history teacher didn't seem to care that I couldn't remember the date of the Stamp Act as long as I could write a comprehensive essay on the significance of the act on American history. (Remember that for a global learner, principles are much easier to remember than details.)
These are people who have been given marvelous creative gifts. With the support of parents and teachers who encourage these gifts instead of trying to remediate them away, these children can become happy, creatively contributing adults.
I am a gifted person who not only learns differently, but who also has unusual abilities. I am not a "disabled" person to be fixed, but a person with many gifts to be shared. I will always struggle with doing detailed tasks while most people struggle with creative tasks. We each can soar when we are allowed to learn in the way our brain processes information. Some people do not think in the most common way, but that certainly does not make them "disabled" unless they come to see themselves as crippled beings and do not develop their potential.
When reading this information, keep in mind that most information about about "learning Disabilities" is written by people who view learning differences as something to be "fixed". They endlessly want to drill these children trying to make them into "normal" outgoing, detailed type people. Who wants to be made-over? How would you feel if you were put in remediation until you could write, draw, do sports, or art like a creative person? I know how much it hurts to have your abilities dismissed and for people to try and "help" you to do things in ways that, for you, are unnatural and awkward. We all deserve to have our differences accepted, to be loved, and to be supported in becoming who we really are.