Classification of alcohols. 
  All alcohols, а principle, can be divided into two 
  broad categories i.е. aliphatic alcohols and 
  aromatic alcohols. 
  1. Aliphatic alcohols. Alcohols in which the 
  hydroxyl group is linked an aliphatic carbon chain 
  are called aliphatic alcohols. 
 For example, 
     Methyl alcohol        Ethyl alcohol               Isopropyl alcohol 
      Methanol               Ethanol                      2-Propanol
   2. Aromatic alcohols. Alcohols in which the hydroxyl group is present in the side 
   chain of an aromatic hydrocarbon are called aromatic For example. 
          phenylmethanol                             2-phenylethanol
          (benzyl alcohol)                              (-phenylethyl alcohol)
   Alcohols are further classified as monohydric, dihydric, trihydric and 
   роlyhydric according as their molecules contain one, two, three, or many 
   hydroxyl groups respectively. For ехаmрlе,
      Ethyl alcohol                1,2-Ethanediol                  1,2,3-propanetriol
      (Monohydric)                (Dihydric)                         (Trihydric)
   2. Aromatic alcohols. Alcohols in which the hydroxyl group is present in the side 
   chain of an aromatic hydrocarbon are called aromatic For example. 
          phenylmethanol                             2-phenylethanol
          (benzyl alcohol)                              (-phenylethyl alcohol)
   Alcohols are further classified as monohydric, dihydric, trihydric and 
   роlyhydric according as their molecules contain one, two, three, or many 
   hydroxyl groups respectively. For ехаmрlе,
      Ethyl alcohol                1,2-Ethanediol                  1,2,3-propanetriol
      (Monohydric)                (Dihydric)                         (Trihydric)
  I. Тhe alkyl alcohol system. In this system of common 
     nomenclature, the name of an alcohol is derived by combining 
     the name of the alkyl group with the word alcohol. The names 
     are mitten as two words.
  n-butyl alcohol                      isobutyl alcohol                   tret-butyl alcohol
  II. In this common system, the position of an additional substituent is 
     indicated by use of the Greek alphabet rather than by 
     numbers.
      -chloroethyl alcohol              -bromobutyl alcohol
   Any simple radical that has а common name may be used in the 
   alkyl alcohol system, with one important exception. The grouping 
   С6Н5 - has the special name phenyl, but the compound C6H5OH is 
   phenol, not phenyl alcohol. 
               phenol 
   Substituted phenols are named as derivatives of the parent compound phenol. 
   The reason for this difference is historical and arose from the fact that phenol 
   and its derivatives have many chemical properties that are very different from 
   those of alkyl alcohols. However, phenyl substituted alkyl alcohols are normal 
   alcohols and often have common names.  Examples are:
                  phenylmethanol                                             2-phenylethanol 
                              (benzyl alcohol)                        (                      -phenylethyl alcohol