[1] : The Collaborative International Dictionary of English v.0.48

bitter \bit"ter\, a. as. biter; akin to goth. baitrs, icel.
   bitr, dan., sw., d.,  g. bitter, os. bittar, fr. root of e.
   bite. see bite, v. t.
   1. having a peculiar, acrid, biting taste, like that of
      wormwood or an infusion of hops; as, a bitter medicine;
      bitter as aloes.
      1913 webster

   2. causing pain or smart; piercing; painful; sharp; severe;
      as, a bitter cold day.
      1913 webster

   3. causing, or fitted to cause, pain or distress to the mind;
      calamitous; poignant.
      1913 webster

            it is an evil thing and bitter, that thou hast
            forsaken the lord thy god.            --jer. ii. 19.
      1913 webster

   4. characterized by sharpness, severity, or cruelty; harsh;
      stern; virulent; as, bitter reproach.
      1913 webster

            husbands, love your wives, and be not bitter against
            them.                                 --col. iii.
                                                  19.
      1913 webster

   5. mournful; sad; distressing; painful; pitiable.
      1913 webster

            the egyptians . . . made their lives bitter with
            hard bondage.                         --ex. i. 14.
      1913 webster

   bitter apple, bitter cucumber, bitter gourd. bot. see
      colocynth.

   bitter cress bot., a plant of the genus cardamine, esp.
      cardamine amara.

   bitter earth min., tale earth; calcined magnesia.

   bitter principles chem., a class of substances, extracted
      from vegetable products, having strong bitter taste but
      with no sharply defined chemical characteristics.

   bitter salt, epsom salts; magnesium sulphate.

   bitter vetch bot., a name given to two european
      leguminous herbs, vicia orobus and ervum ervilia.

   to the bitter end, to the last extremity, however
      calamitous.
      1913 webster

   syn: acrid; sharp; harsh; pungent; stinging; cutting; severe;
        acrimonious.
        1913 webster
see also:
bite bitter apple bitter cucumber bitter gourd colocynth bitter cress 
cardamine cardamine amara bitter earth bitter principles bitter salt 
bitter vetch vicia orobus ervum ervilia to the bitter end 

[2] : The Collaborative International Dictionary of English v.0.48

ers \ers\, n. f., fr. l. ervum a kind of pulse, bitter vetch.
   bot.
   the bitter vetch ervum ervilia.
   1913 webster
see also:
ervum ervilia 

Ervum >> E Words
Ervum, definition of term: Ervum
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