The Collaborative International Dictionary of English v.0.48:

Scissors \Scis"sors\, n. pl. [OE. sisoures, OF. cisoires (cf. F.
   ciseaux), probably fr. LL. cisorium a cutting instrument, fr.
   L. caedere to cut. Cf. Chisel, Concise. The modern
   spelling is due to a mistaken derivation from L. scissor one
   who cleaves or divides, fr. scindere, scissum, to cut,
   split.]
   A cutting instrument resembling shears, but smaller,
   consisting of two cutting blades with handles, movable on a
   pin in the center, by which they are held together. Often
   called a pair of scissors. [Formerly written also cisors,
   cizars, and scissars.]
   [1913 Webster]

   Scissors grinder (Zool.), the European goatsucker. [Prov.
      Eng.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

pair of scissors
    n 1: an edge tool having two crossed pivoting blades [syn:
         scissors, pair of scissors]