[ see-nahyl, -nil, sen-ahyl ]
/ ˈsi naɪl, -nɪl, ˈsɛn aɪl /


showing a decline or deterioration of physical strength or mental functioning, especially short-term memory and alertness, as a result of old age or disease.
of or belonging to old age or aged persons; gerontological; geriatric.
Physical Geography. (of topographical features) having been reduced by erosion to a featureless plain that stands everywhere at base level.Compare peneplain.


a senile person.

Nearby words

  1. sengstaken-blakemore tube,
  2. senhor,
  3. senhora,
  4. senhorita,
  5. senicide,
  6. senile amyloidosis,
  7. senile arteriosclerosis,
  8. senile cataract,
  9. senile dementia,
  10. senile elastosis

Origin of senile

1655–65; < Latin senīlis old, equivalent to sen(ex) old man (akin to senior) + -īlis -ile

Related formsun·se·nile, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for senile

British Dictionary definitions for senile


/ (ˈsiːnaɪl) /


of, relating to, or characteristic of old age
mentally or physically weak or infirm on account of old age
(of land forms or rivers) at an advanced stage in the cycle of erosionSee old (def. 18)
Derived Formssenilely, adverbsenility (sɪˈnɪlɪtɪ), noun

Word Origin for senile

C17: from Latin senīlis, from senex an old man

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for senile



1660s, "suited to old age," from French sénile (16c.), from Latin senilis "of old age," from senex (genitive senis) "old, old man," from PIE root *sen- "old" (cf. Sanskrit sanah "old;" Avestan hana- "old;" Old Persian hanata- "old age, lapse of time;" Armenian hin "old;" Greek enos "old, of last year;" Lithuanian senas "old," senis "an old man;" Gothic sineigs "old" (used only of persons), sinistra "elder, senior;" Old Norse sina "dry standing grass from the previous year;" Old Irish sen, Old Welsh hen "old"). Meaning "weak or infirm from age" is first attested 1848.

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for senile


[ sēnīl′, sĕnīl′ ]


Relating to, characteristic of, or resulting from old age.
Exhibiting the symptoms of senility, as impaired memory or the inability to perform certain mental tasks.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.