The Collaborative International Dictionary of English v.0.48:

Twilight \Twi"light`\, n. [OE. twilight, AS. twi- (see Twice)
   + le['o]ht light; hence the sense of doubtful or half light;
   cf. LG. twelecht, G. zwielicht. See Light.]
   [1913 Webster]
   1. The light perceived before the rising, and after the
      setting, of the sun, or when the sun is less than 18[deg]
      below the horizon, occasioned by the illumination of the
      earth's atmosphere by the direct rays of the sun and their
      reflection on the earth.
      [1913 Webster]

   2. faint light; a dubious or uncertain medium through which
      anything is viewed.
      [1913 Webster]

            As when the sun . . . from behind the moon,
            In dim eclipse, disastrous twilight sheds. --Milton.
      [1913 Webster]

            The twilight of probability.          --Locke.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Twilight \Twi"light`\, a.
   1. Seen or done by twilight. --Milton.
      [1913 Webster]

   2. Imperfectly illuminated; shaded; obscure.
      [1913 Webster]

            O'er the twilight groves and dusky caves. --Pope.
      [1913 Webster]

WordNet (r) 3.0 (2006):

twilight
    adj 1: lighted by or as if by twilight; "The dusky night rides
           down the sky/And ushers in the morn"-Henry Fielding; "the
           twilight glow of the sky"; "a boat on a twilit river"
           [syn: dusky, twilight(a), twilit]
    n 1: the time of day immediately following sunset; "he loved the
         twilight"; "they finished before the fall of night" [syn:
         twilight, dusk, gloaming, gloam, nightfall,
         evenfall, fall, crepuscule, crepuscle]
    2: the diffused light from the sky when the sun is below the
       horizon but its rays are refracted by the atmosphere of the
       earth
    3: a condition of decline following successes; "in the twilight
       of the empire"

Moby Thesaurus II by Grady Ward, 1.0:

81 Moby Thesaurus words for "twilight":
   afterglow, alpenglow, aurora, bad light, brown of dusk, brownness,
   candlelight, candlelighting, cocklight, crepuscular, crepuscule,
   dark, darkening, darkish, darkishness, darkling, darksome,
   darksomeness, dawnlight, deadness, decay, declination, decline,
   dim, dim light, diminution, dimming, dimness, dimpsy, downturn,
   drabness, dullness, dusk, duskiness, duskingtide, duskness, dusky,
   ebb, end, evening, evensong, eventide, first light, flatness,
   foredawn, gloam, gloaming, glooming, gloomy, glow, half-light,
   lack of sparkle, lackluster, lifelessness, limbo, lusterlessness,
   mat, mat finish, morning twilight, murk, murkiness, nightfall,
   obscure, owllight, partial darkness, semidark, shadowy, shady,
   slump, somberness, sundown, sunset, sunsetty, the small hours,
   twilight zone, twilighty, vesper, vespertine, wane, waning,
   weakening



U.S. Gazetteer Places (2000):

Twilight, PA -- U.S. borough in Pennsylvania
   Population (2000):    241
   Housing Units (2000): 103
   Land area (2000):     1.607736 sq. miles (4.164016 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    1.607736 sq. miles (4.164016 sq. km)
   FIPS code:            78008
   Located within:       Pennsylvania (PA), FIPS 42
   Location:             40.114307 N, 79.890369 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Twilight, PA
    Twilight