What's the difference between i.e. and e.g.?
1903, coined in English from Greek geron (genitive gerontos) "old man," from PIE root *gere- "to become ripe, grow old" (cf. Sanskrit jara "old age," jarati "makes frail, causes to age;" Avestan zaurvan "old age;" Ossetic zarond "old man;" Armenian cer "old, old man").
gerontology ger·on·tol·o·gy (jěr'ən-tŏl'ə-jē)
The scientific study of the biological, psychological, and sociological phenomena that are associated with old age and aging.
A medical specialty that focuses on the care and treatment of the elderly.
Note: The large number of aging “baby boomers” has increased both the profile and importance of this specialty.