Definition of "senile" [se•nile]

• Of, relating to, or characteristic of old age. (adjective)
• Relating to or exhibiting memory loss or mental impairment associated with aging. (adjective)
• Geology Worn away nearly to the base level, as at the end of an erosion cycle. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "For John McCain to think that "losing one's bearings" impys "is old and senile" is totally incorrect."
• "As a direct consequence we may increase our understanding of many disease states such as developmental malformations, degenerative changes in senile dementia, delayed wound healing and tumour diseases."
• "However, this knowledge can be expected to improve our understanding of the pathogenesis of several clinical disorders such as malformation and errors of development, degenerative changes such as occur in senile dementia, delayed wound healing, muscle dystrophy as well as tumour diseases."