elder (adj.) Look up elder at Dictionary.com
"more old," Old English (Mercian) eldra, comparative of eald, ald (see old); only English survival of umlaut in comparison. Superseded by older since 16c. Elder statesman (1921) originally was a translation of Japanese genro (plural).
elder (n.1) Look up elder at Dictionary.com
"elderly person, senior citizen," c. 1200, from Old English eldra "older person, parent; ancestor; chief, prince" (used in biblical translation for Greek presbyter); see elder (adj.). Compare German Eltern, Danish forældre, Swedish föräldrar "parents." The Old English for "grandfather" was ealdfæder.
elder (n.2) Look up elder at Dictionary.com
type of berry tree, c. 1400, from earlier ellen, from Old English ellæn, ellærn "elderberry tree," origin unknown, perhaps related to alder, which at any rate might be the source of the unetymological -d-. Common Germanic, cognates: Old Saxon elora, Middle Low German elre, Old High German elira, German Eller, Erle. Related: Elderberry.