Definition of Senile

Senile: 1. Pertaining to old age. 2. Pertaining to the physical decline associated with old age. 3. Pertaining to the mental decline once associated with old age but now known to be due to dementia, such as Alzheimer's disease or cerebral atherosclerosis. "The road to senility is paved with plaques." (Paul F. Wehrle, MD [1921-2004] pediatrician and vaccine researcher)

From the Latin senilis, from senectus meaning old age, old men, gray hair. See also: Senile chorea; Senile keratosis; Senile lentigo