Aphasia refers to the loss or impairment of previously acquired abilities in language comprehension or production that cannot be explained by sensory or motor defects or by diffuse brain dysfunction.
Other /More definition:
Aphasia refers to a loss of the ability to use language.
Other /More definition:
Aphasia refers to the impairment or loss of language skills resulting from brain damage caused by stroke, Alzheimer’s disease, or other illness or trauma. Also, a person's loss of the ability to use language.