Source : Webster's Revised Unabridged Dictionary (1913)

Scallion \Scal"lion\, n. [OF. escalone, eschaloingne, L. caepa
   Ascalonia onion of Ascalon; caepa onion + Ascalonius of
   Ascalon, fr. Ascalo Ascalon, a town in Palestine. Cf.
   {Shallot}.]
   1. (Bot.) A kind of small onion ({Allium Ascalonicum}),
      native of Palestine; the eschalot, or shallot.

   2. Any onion which does not ``bottom out,'' but remains with
      a thick stem like a leek. --Amer. Cyc.

Shallot \Shal*lot"\, n. [OF. eschalote (for escalone), F.
   ['e]chalote. See {Scallion}, and cf. {Eschalot}.] (Bot.)
   A small kind of onion ({Allium Ascalonicum}) growing in
   clusters, and ready for gathering in spring; a scallion, or
   eschalot.

Source : WordNet®

Allium ascalonicum
     n : type of onion plant producing small clustered mild-flavored
         bulbs used as seasoning [syn: {shallot}, {eschalot}, {multiplier
         onion}, {Allium cepa aggregatum}]