1903, coined in English from geronto-, used as comb. form of Greek geron (genitive gerontos) "old man," from PIE root *gere- "to become ripe, grow old" (cognates: Sanskrit jara "old age," jarati "makes frail, causes to age;" Avestan zaurvan "old age;" Ossetic zarond "old man;" Armenian cer "old, old man").[gerontology etymology, gerontology origin, 英语词源]