Can someone tell me the definition for secondary diagnosis?

The primary diagnosis is what put you in the hospital in the first place. All secondary diagnoses are those that may have contributed to the primary or may not have, but they are definitely conditions that must be dealt with in order to treat your total health.

In regards to school or doctor office, (if that is what you are asking) a secondary LD is one that is there, and needs assistance, but the needs are not as dire or as needed as the primary.

For example, my daughters primary LD is reading comprehension/problem solving/prediction.
Her secondary is material absorption. Because she CAN absorb the material, it is just difficult for her and she requires little intervention to do it. But at this point she seems incapable of reading part of a story, and understanding what happened, or coming to a conclusion of what might happen next.