The Collaborative International Dictionary of English v.0.48:

Foster \Fos"ter\, v. t. [imp. & p. p. Fostered, p. pr. & vb.
   n. Fostering.] [OE. fostren, fr. AS. f[=o]ster, f[=o]stor,
   food, nourishment, fr. f[=o]da food. [root]75. See Food.]
   1. To feed; to nourish; to support; to bring up.
      [1913 Webster]

            Some say that ravens foster forlorn children.
                                                  --Shak.
      [1913 Webster]

   2. To cherish; to promote the growth of; to encourage; to
      sustain and promote; as, to foster genius.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Foster \Fos"ter\, v. i.
   To be nourished or trained up together. [Obs.] --Spenser.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Foster \Fos"ter\, a. [AS. f[=o]ster, f[=o]stor, nourishment. See
   Foster, v. t.]
   Relating to nourishment; affording, receiving, or sharing
   nourishment or nurture; -- applied to father, mother, child,
   brother, etc., to indicate that the person so called stands
   in the relation of parent, child, brother, etc., as regards
   sustenance and nurture, but not by tie of blood.
   [1913 Webster]

   Foster babe or Foster child, an infant or child nursed or
      raised by a woman not its mother, or bred by a man not its
      father.

   Foster brother, Foster sister, one who is, or has been,
      nursed at the same breast, or brought up by the same nurse
      as another, but is not of the same parentage.

   Foster dam, one who takes the place of a mother; a nurse.
      --Dryden.

   Foster earth, earth by which a plant is nourished, though
      not its native soil. --J. Philips.

   Foster father, a man who takes the place of a father in
      caring for a child. --Bacon.

   Foster land.
   (a) Land allotted for the maintenance of any one. [Obs.]
   (b) One's adopted country.

   Foster lean [foster + AS. l[ae]n a loan See Loan.],
      remuneration fixed for the rearing of a foster child;
      also, the jointure of a wife. [Obs.] --Wharton.

   Foster mother, a woman who takes a mother's place in the
      nurture and care of a child; a nurse.

   Foster nurse, a nurse; a nourisher. [R.] --Shak.

   Foster parent, a foster mother or foster father.

   Foster son, a male foster child.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Foster \Fos"ter\, n.
   A forester. [Obs.] --Spenser.
   [1913 Webster]

WordNet (r) 3.0 (2006):

foster
    adj 1: providing or receiving nurture or parental care though
           not related by blood or legal ties; "foster parent";
           "foster child"; "foster home"; "surrogate father" [syn:
           foster, surrogate]
    n 1: United States songwriter whose songs embody the sentiment
         of the South before the American Civil War (1826-1864)
         [syn: Foster, Stephen Foster, Stephen Collins Foster]
    v 1: promote the growth of; "Foster our children's well-being
         and education" [syn: foster, further]
    2: bring up under fosterage; of children
    3: help develop, help grow; "nurture his talents" [syn:
       foster, nurture]

Moby Thesaurus II by Grady Ward, 1.0:

199 Moby Thesaurus words for "foster":
   abet, accommodate, acculturate, actuate, advance, affiliated,
   agnate, aid, aid and abet, akin, aliment, allied, ameliorate,
   amend, animate, apprentice, ask for, assist, attend to, avuncular,
   baby-sit, back, bear, better, boost, bosom, break, break in,
   breast-feed, breed, bring forward, bring up, care for, champion,
   chaperon, cherish, civilize, cling to, clip, closely related,
   coddle, cognate, collateral, compel, condition, congeneric,
   consanguine, consanguinean, consanguineous, conserve,
   contribute to, cosset, countenance, cradle, cultivate, develop,
   discipline, distantly related, drill, dry-nurse, edify, educate,
   elevate, embosom, embrace, emend, enate, encourage, energize,
   enhance, enlighten, enrich, entertain, exercise, fatten, fatten up,
   favor, feed, fetch up, fit, fondle, force, force-feed, form,
   forward, further, galvanize, german, germane, give encouragement,
   go straight, groom, harbor, hasten, have, have and hold, help,
   hold, hold on to, house, house-train, housebreak, hug, impel,
   improve, improve upon, invite, keep, keep in countenance,
   keep watch over, kindred, lactate, lard, lavish care on,
   lick into shape, lift, lodge, look after, look out for, look to,
   maintain, make an improvement, matrilateral, matrilineal,
   matroclinous, matronize, meliorate, mend, mind, minister to,
   mother, motivate, move, move to action, nourish, novercal, nurse,
   nurture, nutrify, oblige, of the blood, pamper, patrilateral,
   patrilineal, patroclinous, patronize, practice, prepare, preserve,
   promote, propel, protege, provide for, put in tune, put to school,
   raise, ready, rear, refine upon, reform, rehearse, related,
   ride herd on, see after, see to, send to school, serve,
   set in motion, shelter, shepherd, sib, sibling, socialize, spark,
   spoon-feed, stimulate, straighten out, stuff, succor, suckle,
   support, sustain, take care of, take charge of, take in hand, tend,
   train, transfigure, transform, treasure, treasure up, upgrade,
   uphold, uplift, uterine, watch, watch out for, watch over,
   wet-nurse



U.S. Gazetteer Counties (2000):

Foster -- U.S. County in North Dakota
   Population (2000):    3759
   Housing Units (2000): 1793
   Land area (2000):     635.200527 sq. miles (1645.161743 sq. km)
   Water area (2000):    11.516196 sq. miles (29.826810 sq. km)
   Total area (2000):    646.716723 sq. miles (1674.988553 sq. km)
   Located within:       North Dakota (ND), FIPS 38
   Location:             47.464369 N, 98.894282 W
   Headwords:
    Foster
    Foster, ND
    Foster County
    Foster County, ND


U.S. Gazetteer Places (2000):

Foster, NE -- U.S. village in Nebraska
   Population (2000):    63
   Housing Units (2000): 34
   Land area (2000):     0.216290 sq. miles (0.560188 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.216290 sq. miles (0.560188 sq. km)
   FIPS code:            17320
   Located within:       Nebraska (NE), FIPS 31
   Location:             42.273681 N, 97.665357 W
   ZIP Codes (1990):     68737
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Foster, NE
    Foster


U.S. Gazetteer Places (2000):

Foster, MO -- U.S. village in Missouri
   Population (2000):    130
   Housing Units (2000): 63
   Land area (2000):     0.468388 sq. miles (1.213119 sq. km)
   Water area (2000):    0.004659 sq. miles (0.012067 sq. km)
   Total area (2000):    0.473047 sq. miles (1.225186 sq. km)
   FIPS code:            25372
   Located within:       Missouri (MO), FIPS 29
   Location:             38.165674 N, 94.507017 W
   ZIP Codes (1990):     64745
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Foster, MO
    Foster