The definition provided in US federal code (Section 300.7(c) (10) of 34 CFR Parts 300 and 303) :
(i) General. The term means a disorder in one or more of the basic psychological processes involved in understanding or in using language, spoken or written, that may manifest itself in an imperfect ability to listen, think, speak, read, write, spell, or to do mathematical calculations, including conditions such as perceptual disabilities, brain injury, minimal brain dysfunction, dyslexia, and developmental aphasia.
(ii) Disorders not included. The term does not include learning problems that are primarily the result of visual, hearing, of motor disabilities, of mental retardation, of emotional disturbance, or of environmental, cultural, or economic disadvantage.
The definition provided in the Diagnostic and Statistical Manual of mental disorder fourth edition Text Revised(DSM- IV-TR)
The section of Learning Disorder include Reading Disorder, Mathematics Disorder, Disorder of Written Expression and Learning Disorder Not otherwise specified
• Diagnostic criteria for Reading Disorder
• Diagnostic criteria for Mathematics Disorder
• Diagnostic criteria for Disorder of written Expression
International classification of mental and behavioural disorders-10 [ICD-10]
Specific Developmental Disorders of Scholastic Skills
• F81.0 Specific reading disorder
• F81.1 Specific spelling disorder
• F81.2 Specific disorder of arithmetical skills
• F81.3 Mixed disorder of scholastic skills
This is an ill-defined, inadequately conceptualized (but necessary) residual category of disorders in which both arithmetical and reading or spelling skills are significantly impaired, but in which the disorder is not solely explicable in terms of general mental retardation or inadequate schooling. It should be used for disorders meeting the criteria for F81.2 and either F81.0 or F81.1.
• F81.8 Other developmental disorders of scholastic skills
• F81.9 Developmental disorder of scholastic skills, unspecified
This category should be avoided as far as possible and should be used only for unspecified disorders in which there is a significant disability of learning that cannot be solely accounted for by mental retardation, visual acuity problems, or inadequate schooling.