The Collaborative International Dictionary of English v.0.48:

ampule \ampule\ n.
   1. a small glass bottle which has been or can be sealed
      hermetically by application of flame to a narrow opening
      at the top.

   Note: aAn ampule usually has a narrow constriction near the
         top which can be scored and easily broken to open the
         ampule. Once opened, they cannot be hermetically
         re-sealed; thus the quantity contained is usually that
         which is to be used at once or within a short time. The
         contents are often sealed under vacuum to retard
         degradation by air.

   Syn: phial, vial, ampoule
        [WordNet 1.5]

   2. an ampule, or vial resembling an ampule, which contains a
      drug.
      [PJC]

WordNet (r) 3.0 (2006):

ampule
    n 1: a small bottle that contains a drug (especially a sealed
         sterile container for injection by needle) [syn: phial,
         vial, ampule, ampul, ampoule]