The Collaborative International Dictionary of English v.0.48:

Summit \Sum"mit\, n. [F. sommet, dim. of OF. som, sum, top, from
   L. summum, from summus highest. See Sum, n.]
   1. The top; the highest point.
      [1913 Webster]

            Fixed on the summit of the highest mount. --Shak.
      [1913 Webster]

   2. The highest degree; the utmost elevation; the acme; as,
      the summit of human fame.
      [1913 Webster]

   3. (Zool.) The most elevated part of a bivalve shell, or the
      part in which the hinge is situated.
      [1913 Webster]

   Summit level, the highest level of a canal, a railroad, or
      the like, in surmounting an ascent.
      [1913 Webster]

WordNet (r) 3.0 (2006):

summit
    n 1: the highest level or degree attainable; the highest stage
         of development; "his landscapes were deemed the acme of
         beauty"; "the artist's gifts are at their acme"; "at the
         height of her career"; "the peak of perfection"; "summer
         was at its peak"; "...catapulted Einstein to the pinnacle
         of fame"; "the summit of his ambition"; "so many highest
         superlatives achieved by man"; "at the top of his
         profession" [syn: acme, height, elevation, peak,
         pinnacle, summit, superlative, meridian, tiptop,
         top]
    2: the top or extreme point of something (usually a mountain or
       hill); "the view from the peak was magnificent"; "they
       clambered to the tip of Monadnock"; "the region is a few
       molecules wide at the summit" [syn: peak, crown, crest,
       top, tip, summit]
    3: a meeting of heads of governments [syn: summit, summit
       meeting]
    v 1: reach the summit (of a mountain); "They breasted the
         mountain"; "Many mountaineers go up Mt. Everest but not all
         summit" [syn: summit, breast]

Moby Thesaurus II by Grady Ward, 1.0:

107 Moby Thesaurus words for "summit":
   acme, acme of perfection, all, apex, apogee, audience, bargaining,
   bargaining session, brow, cap, capstone, ceiling, climax,
   cloud nine, conclave, confab, confabulation, conference,
   confrontation, congress, consultation, consummation, convention,
   council, council fire, council of war, crest, crown, culmen,
   culmination, discussion, edge, end, exchange of views, extreme,
   extreme limit, extremity, eyeball-to-eyeball encounter, heaven,
   heavens, height, high noon, high-level talk, highest degree,
   highest pitch, highest point, hilltop, huddle,
   interchange of views, interview, knoll, last word, limit,
   lofty peak, maximum, meeting, meridian, mountaintop, ne plus ultra,
   negotiations, news conference, no place higher, noon, nth degree,
   palaver, parley, peak, perfection, pic, pico, pike, pink,
   pink of perfection, pinnacle, pitch, point, pole, pourparler,
   powwow, precipice, press conference, ridge, roof, seance, session,
   seventh heaven, sitting, sky, spire, spur, summit conference,
   summitry, the whole, tip, tip-top, top, tor, ultimate, upmost,
   upper extremity, uppermost, utmost, utmost extent, uttermost,
   vertex, very top, zenith



U.S. Gazetteer Counties (2000):

Summit -- U.S. County in Ohio
   Population (2000):    542899
   Housing Units (2000): 230880
   Land area (2000):     412.723297 sq. miles (1068.948386 sq. km)
   Water area (2000):    7.338126 sq. miles (19.005659 sq. km)
   Total area (2000):    420.061423 sq. miles (1087.954045 sq. km)
   Located within:       Ohio (OH), FIPS 39
   Location:             41.095605 N, 81.520637 W
   Headwords:
    Summit
    Summit, OH
    Summit County
    Summit County, OH


U.S. Gazetteer Counties (2000):

Summit -- U.S. County in Utah
   Population (2000):    29736
   Housing Units (2000): 17489
   Land area (2000):     1871.047522 sq. miles (4845.990629 sq. km)
   Water area (2000):    10.998556 sq. miles (28.486127 sq. km)
   Total area (2000):    1882.046078 sq. miles (4874.476756 sq. km)
   Located within:       Utah (UT), FIPS 49
   Location:             40.828522 N, 111.273030 W
   Headwords:
    Summit
    Summit, UT
    Summit County
    Summit County, UT


U.S. Gazetteer Counties (2000):

Summit -- U.S. County in Colorado
   Population (2000):    23548
   Housing Units (2000): 24201
   Land area (2000):     608.161860 sq. miles (1575.131920 sq. km)
   Water area (2000):    11.089165 sq. miles (28.720803 sq. km)
   Total area (2000):    619.251025 sq. miles (1603.852723 sq. km)
   Located within:       Colorado (CO), FIPS 08
   Location:             39.574638 N, 106.070643 W
   Headwords:
    Summit
    Summit, CO
    Summit County
    Summit County, CO


U.S. Gazetteer Places (2000):

Summit, AZ -- U.S. Census Designated Place in Arizona
   Population (2000):    3702
   Housing Units (2000): 1259
   Land area (2000):     10.120625 sq. miles (26.212298 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    10.120625 sq. miles (26.212298 sq. km)
   FIPS code:            70240
   Located within:       Arizona (AZ), FIPS 04
   Location:             32.063213 N, 110.943549 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Summit, AZ
    Summit


U.S. Gazetteer Places (2000):

Summit, AR -- U.S. city in Arkansas
   Population (2000):    586
   Housing Units (2000): 280
   Land area (2000):     1.225333 sq. miles (3.173598 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    1.225333 sq. miles (3.173598 sq. km)
   FIPS code:            67940
   Located within:       Arkansas (AR), FIPS 05
   Location:             36.250212 N, 92.687592 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Summit, AR
    Summit


U.S. Gazetteer Places (2000):

Summit, NJ -- U.S. city in New Jersey
   Population (2000):    21131
   Housing Units (2000): 8146
   Land area (2000):     6.053503 sq. miles (15.678499 sq. km)
   Water area (2000):    0.021436 sq. miles (0.055519 sq. km)
   Total area (2000):    6.074939 sq. miles (15.734018 sq. km)
   FIPS code:            71430
   Located within:       New Jersey (NJ), FIPS 34
   Location:             40.716201 N, 74.362459 W
   ZIP Codes (1990):     07901
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Summit, NJ
    Summit


U.S. Gazetteer Places (2000):

Summit, OK -- U.S. town in Oklahoma
   Population (2000):    226
   Housing Units (2000): 73
   Land area (2000):     0.912003 sq. miles (2.362077 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.912003 sq. miles (2.362077 sq. km)
   FIPS code:            71450
   Located within:       Oklahoma (OK), FIPS 40
   Location:             35.665561 N, 95.425232 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Summit, OK
    Summit


U.S. Gazetteer Places (2000):

Summit, IL -- U.S. village in Illinois
   Population (2000):    10637
   Housing Units (2000): 3552
   Land area (2000):     2.123687 sq. miles (5.500324 sq. km)
   Water area (2000):    0.153506 sq. miles (0.397578 sq. km)
   Total area (2000):    2.277193 sq. miles (5.897902 sq. km)
   FIPS code:            73638
   Located within:       Illinois (IL), FIPS 17
   Location:             41.788530 N, 87.813909 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Summit, IL
    Summit


U.S. Gazetteer Places (2000):

Summit, SC -- U.S. town in South Carolina
   Population (2000):    219
   Housing Units (2000): 103
   Land area (2000):     1.507531 sq. miles (3.904487 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    1.507531 sq. miles (3.904487 sq. km)
   FIPS code:            70315
   Located within:       South Carolina (SC), FIPS 45
   Location:             33.924475 N, 81.423098 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Summit, SC
    Summit


U.S. Gazetteer Places (2000):

Summit, SD -- U.S. town in South Dakota
   Population (2000):    281
   Housing Units (2000): 144
   Land area (2000):     0.376049 sq. miles (0.973963 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.376049 sq. miles (0.973963 sq. km)
   FIPS code:            62220
   Located within:       South Dakota (SD), FIPS 46
   Location:             45.303743 N, 97.037106 W
   ZIP Codes (1990):     57266
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Summit, SD
    Summit


U.S. Gazetteer Places (2000):

Summit, WA -- U.S. Census Designated Place in Washington
   Population (2000):    8041
   Housing Units (2000): 3090
   Land area (2000):     5.166308 sq. miles (13.380677 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    5.166308 sq. miles (13.380677 sq. km)
   FIPS code:            68365
   Located within:       Washington (WA), FIPS 53
   Location:             47.167657 N, 122.358616 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Summit, WA
    Summit


U.S. Gazetteer Places (2000):

Summit, MS -- U.S. town in Mississippi
   Population (2000):    1428
   Housing Units (2000): 658
   Land area (2000):     1.682166 sq. miles (4.356790 sq. km)
   Water area (2000):    0.000707 sq. miles (0.001830 sq. km)
   Total area (2000):    1.682873 sq. miles (4.358620 sq. km)
   FIPS code:            71480
   Located within:       Mississippi (MS), FIPS 28
   Location:             31.282793 N, 90.466773 W
   ZIP Codes (1990):     39666
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Summit, MS
    Summit