Source : Webster's Revised Unabridged Dictionary (1913)

Ellipsis \El*lip"sis\, n.; pl. {Ellipses}. [L., fr. Gr. ? a
   leaving, defect, fr. ? to leave in fall short; ? in + ? to
   leave. See {In}, and {Loan}, and cf. {Ellipse}.]
   1. (Gram.) Omission; a figure of syntax, by which one or more
      words, which are obviously understood, are omitted; as,
      the virtues I admire, for, the virtues which I admire.

   2. (Geom.) An ellipse. [Obs.]

Source : WordNet®

ellipsis
     n : omission or suppression of parts of words or sentences [syn:
          {eclipsis}]
     [also: {ellipses} (pl)]