'By far' definitions:

Definition of 'by far'

(from WordNet)
adverb
By a considerable margin; "she was by far the smartest student"; "it was far and away the best meal he had ever eaten" [syn: by far, far and away, out and away]

Definition of 'By far'

From: GCIDE
  • Far \Far\, a. [Fartherand Farthestare used as the compar. and superl. of far, although they are corruptions arising from confusion with further and furthest. See Further.] [OE. fer, feor, AS. feor; akin to OS. fer, D. ver, OHG. ferro, adv., G. fern, a., Icel. fjarri, Dan. fjirn, Sw. fjerran, adv., Goth. fa[imac]rra, adv., Gr. ????? beyond, Skr. paras, adv., far, and prob. to L. per through, and E. prefix for-, as in forgive, and also to fare. Cf. Farther, Farthest.]
  • 1. Distant in any direction; not near; remote; mutually separated by a wide space or extent. [1913 Webster]
  • They said, . . . We be come from a far country. --Josh. ix. 6. [1913 Webster]
  • The nations far and near contend in choice. --Dryden. [1913 Webster]
  • 2. Remote from purpose; contrary to design or wishes; as, far be it from me to justify cruelty. [1913 Webster]
  • 3. Remote in affection or obedience; at a distance, morally or spiritually; t enmity with; alienated. [1913 Webster]
  • They that are far from thee ahsll perish. --Ps. lxxiii. 27. [1913 Webster]
  • 4. Widely different in nature or quality; opposite in character. [1913 Webster]
  • He was far from ill looking, though he thought himself still farther. --F. Anstey. [1913 Webster]
  • 5. The more distant of two; as, the far side (called also off side) of a horse, that is, the right side, or the one opposite to the rider when he mounts. [1913 Webster]
  • Note: The distinction between the adjectival and adverbial use of far is sometimes not easily discriminated. [1913 Webster]
  • By far, by much; by a great difference.
  • Far between, with a long distance (of space or time) between; at long intervals. "The examinations are few and far between." --Farrar. [1913 Webster]