The Collaborative International Dictionary of English v.0.48:

Elder \Eld"er\, a. [AS. yldra, compar. of eald old. See Old.]
   1. Older; more aged, or existing longer.
      [1913 Webster]

            Let the elder men among us emulate their own earlier
            deeds.                                --Jowett
                                                  (Thucyd. )
      [1913 Webster]

   2. Born before another; prior in years; senior; earlier;
      older; as, his elder brother died in infancy; -- opposed
      to younger, and now commonly applied to a son, daughter,
      child, brother, etc.
      [1913 Webster]

            The elder shall serve the younger.    --Gen. xxv.
                                                  23.
      [1913 Webster]

            But ask of elder days, earth's vernal hour. --Keble.
      [1913 Webster]

   Elder hand (Card Playing), the hand playing, or having the
      right to play, first. --Hoyle.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Elder \El"der\, n. [OE. ellern, eller, AS. ellen, cf. LG.
   elloorn; perh. akin to OHG. holantar, holuntar, G. holunder;
   or perh. to E. alder, n.] (Bot.)
   A genus of shrubs (Sambucus) having broad umbels of white
   flowers, and small black or red berries.
   [1913 Webster]

   Note: The common North American species is Sambucus
         Canadensis; the common European species (S. nigra)
         forms a small tree. The red-berried elder is S.
         pubens. The berries are diaphoretic and aperient. The
         European elder (Sambucus nigra) is also called the
         elderberry, bourtree, Old World elder, black
         elder, and common elder.
         [1913 Webster + WordNet 1.5]

   Box elder. See under 1st Box.

   Dwarf elder. See Danewort.

   Elder tree. (Bot.) Same as Elder. --Shak.

   Marsh elder, the cranberry tree Viburnum Opulus).
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Elder \Eld"er\, n. [AS. ealdor an elder, prince, fr. eald old.
   See Old, and cf. Elder, a., Alderman.]
   1. One who is older; a superior in age; a senior. --1 Tim. v.
      1.
      [1913 Webster]

   2. An aged person; one who lived at an earlier period; a
      predecessor.
      [1913 Webster]

            Carry your head as your elders have done.
                                                  --L'Estrange.
      [1913 Webster]

   3. A person who, on account of his age, occupies the office
      of ruler or judge; hence, a person occupying any office
      appropriate to such as have the experience and dignity
      which age confers; as, the elders of Israel; the elders of
      the synagogue; the elders in the apostolic church.
      [1913 Webster]

   Note: In the modern Presbyterian churches, elders are lay
         officers who, with the minister, compose the church
         session, with authority to inspect and regulate matters
         of religion and discipline. In some churches, pastors
         or clergymen are called elders, or presbyters.
         [1913 Webster]

   4. (M. E. Ch.) A clergyman authorized to administer all the
      sacraments; as, a traveling elder.
      [1913 Webster]

   Presiding elder (Meth. Ch.), an elder commissioned by a
      bishop to have the oversight of the churches and preachers
      in a certain district.

   Ruling elder, a lay presbyter or member of a Presbyterian
      church session. --Schaff.
      [1913 Webster]

WordNet (r) 3.0 (2006):

elder
    adj 1: used of the older of two persons of the same name
           especially used to distinguish a father from his son;
           "Bill Adams, Sr." [syn: elder, older, sr.]
    n 1: a person who is older than you are [syn: elder, senior]
    2: any of numerous shrubs or small trees of temperate and
       subtropical northern hemisphere having white flowers and
       berrylike fruit [syn: elder, elderberry bush]
    3: any of various church officers

Moby Thesaurus II by Grady Ward, 1.0:

288 Moby Thesaurus words for "elder":
   Aaronic priesthood, Bible clerk, Bible reader, Establishment,
   Father Time, Melchizedek priesthood, Methuselah, Nestor, Old Paar,
   Seventy, VIP, acolyte, age, alderman, almoner, anagnost, ancestors,
   antecedent, antecedents, antediluvian, anterior, anticipatory,
   antique, apostle, archon, ascendants, authority, back number,
   bailie, baron, beadle, bedral, big gun, big man, big name, bigwig,
   bishop, boss, brass, brass hat, burghermaster, burgomaster, bwana,
   cabinet member, cabinet minister, caducity, capitular, capitulary,
   celebrity, centenarian, chancellor, chef, chief, choir chaplain,
   church dignitary, churchwarden, ci-devant, city councilman,
   city father, city manager, clerk, commissar, commissioner,
   conservative, councillor, councilman, councilwoman,
   county commissioner, county supervisor, dad, deacon, deaconess,
   dean, dignitary, dignity, doctor, dodo, dotard, doyen, doyenne,
   earlier, early, ecclesiarch, elder statesman, elderliness,
   elderman, elders, eldest, employer, experienced, father, fathers,
   figure, first, first-born, firstling, fogy, fore, forebears,
   forefathers, foregoing, former, fossil, fud, fuddy-duddy, gaffer,
   geezer, golden-ager, goodman, gramps, grandfather, grandfathers,
   grandparents, grandsire, granny, graybeard, great man, great soul,
   guru, has-been, headman, high priest, husband, illuminate,
   important person, induna, intellect, intellectual, interests,
   lay elder, lay reader, lector, lecturer, legislator, liege,
   liege lord, lion, longhair, lord, lord mayor, lord paramount,
   lords of creation, lover of wisdom, magistrate, magnate, mahatma,
   maire, major, man of intellect, man of mark, man of wisdom,
   mandarin, master, mastermind, matriarch, mayor, mentor,
   mid-Victorian, minister, minister of state, mogul, mossback, nabob,
   name, nonagenarian, notability, notable, octogenarian, old age,
   old believer, old chap, old codger, old crock, old dodo, old dog,
   old duffer, old fogy, old geezer, old gent, old gentleman,
   old liner, old man, old party, old poop, old woman, old-timer,
   older, oldest, oldster, oracle, overlord, padrone, panjandrum,
   pantaloon, paramount, parish clerk, paterfamilias, patriarch,
   patriarchs, patron, person of renown, personage, personality,
   philosopher, pillar of society, pop, pops, portreeve, power,
   power elite, preceding, precentor, precurrent, predecessors,
   preexistent, presbyter, previous, priest, prime, primogenitary,
   prior, progenitors, rabbi, reactionary, reader, reeve,
   regular old fogy, relic, respected, rishi, ruling circle,
   ruling elder, sachem, sacrist, sacristan, sage, sahib, sapient,
   savant, scholar, secretary, secretary of state, seer, seigneur,
   seignior, selectman, senectitude, senescence, senior,
   senior citizen, septuagenarian, sexagenarian, sexton, shames,
   sidesman, sire, somebody, something, square, starets, succentor,
   suisse, superior, supervisor, syndic, teacher, teaching elder,
   the great, the quiet-voiced elders, the top, thinker, thurifer,
   top brass, top people, traditionalist, tycoon, undersecretary,
   venerable, venerable sir, verger, vergeress, very important person,
   veteran, warden, wise man, wise old man, worthy, years



Easton's 1897 Bible Dictionary:

Elder
   a name frequently used in the Old Testament as denoting a person
   clothed with authority, and entitled to respect and reverence
   (Gen. 50:7). It also denoted a political office (Num. 22:7). The
   "elders of Israel" held a rank among the people indicative of
   authority. Moses opened his commission to them (Ex. 3:16). They
   attended Moses on all important occasions. Seventy of them
   attended on him at the giving of the law (Ex. 24:1). Seventy
   also were selected from the whole number to bear with Moses the
   burden of the people (Num. 11:16, 17). The "elder" is the
   keystone of the social and political fabric wherever the
   patriarchal system exists. At the present day this is the case
   among the Arabs, where the sheik (i.e., "the old man") is the
   highest authority in the tribe. The body of the "elders" of
   Israel were the representatives of the people from the very
   first, and were recognized as such by Moses. All down through
   the history of the Jews we find mention made of the elders as
   exercising authority among the people. They appear as governors
   (Deut. 31:28), as local magistrates (16:18), administering
   justice (19:12). They were men of extensive influence (1 Sam.
   30:26-31). In New Testament times they also appear taking an
   active part in public affairs (Matt. 16:21; 21:23; 26:59).

     The Jewish eldership was transferred from the old dispensation
   to the new. "The creation of the office of elder is nowhere
   recorded in the New Testament, as in the case of deacons and
   apostles, because the latter offices were created to meet new
   and special emergencies, while the former was transmitted from
   the earlies times. In other words, the office of elder was the
   only permanent essential office of the church under either
   dispensation."

     The "elders" of the New Testament church were the "pastors"
   (Eph. 4:11), "bishops or overseers" (Acts 20:28), "leaders" and
   "rulers" (Heb. 13:7; 1 Thess. 5:12) of the flock. Everywhere in
   the New Testament bishop and presbyter are titles given to one
   and the same officer of the Christian church. He who is called
   presbyter or elder on account of his age or gravity is also
   called bishop or overseer with reference to the duty that lay
   upon him (Titus 1:5-7; Acts 20:17-28; Phil. 1:1).