The Collaborative International Dictionary of English v.0.48:

Notable \Not"a*ble\, a. [F. notable, L. notabilis, fr. notare to
   mark, nota mark, note. See 5th Note.]
   [1913 Webster]
   1. Capable of being noted; noticeable; plain; evident.
      [1913 Webster]

   2. Worthy of notice; remarkable; memorable; noted or
      distinguished; as, a notable event, person.
      [1913 Webster]

   Note: Notable in the sense of careful, thrifty, characterized
         by thrift and capacity (as, a notable housekeeper) is
         pronounced by many good orthoepists, n[o^]t"[.a]*b'l,
         the derivatives notableness, and notably, being also
         similarly pronounced with short o in the first
         syllable.
         [1913 Webster]

   3. Well-known; notorious. [Obs.] --Chaucer.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Notable \Not"a*ble\ (n[=o]t"[.a]*b'l), n.
   1. A person, or thing, of distinction.
      [1913 Webster]

   2. (French Hist.) One of a number of persons, before the
      revolution of 1789, chiefly of the higher orders,
      appointed by the king to constitute a representative body.
      [1913 Webster]

WordNet (r) 3.0 (2006):

notable
    adj 1: worthy of notice; "a noteworthy advance in cancer
           research" [syn: noteworthy, notable]
    2: widely known and esteemed; "a famous actor"; "a celebrated
       musician"; "a famed scientist"; "an illustrious judge"; "a
       notable historian"; "a renowned painter" [syn: celebrated,
       famed, far-famed, famous, illustrious, notable,
       noted, renowned]
    n 1: a celebrity who is an inspiration to others; "he was host
         to a large gathering of luminaries" [syn: luminary,
         leading light, guiding light, notable, notability]