The Collaborative International Dictionary of English v.0.48:

Indo-European \In`do-Eu`ro*pe"an\, a.
   Aryan; -- applied to the languages of India and Europe which
   are derived from the prehistoric Aryan language; also,
   pertaining to the people or nations who speak these
   languages; as, the Indo-European or Aryan family.
   [1913 Webster]

         The common origin of the Indo-European nations.
                                                  --Tylor.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Indo-European \In`do-Eu`ro*pe"an\
   A member of one of the Caucasian races of Europe or India
   speaking an Indo-European language.

         Professor Otto Schrader . . . considers that the oldest
         probable domicile of the Indo-Europeans is to be sought
         for on the common borderland of Asia and of Europe, --
         in the steppe country of southern Russia. --Census of
                                                  India, 1901.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

Indo-European
    adj 1: of or relating to the Indo-European language family [syn:
           Indo-European, Indo-Germanic]
    2: of or relating to the former Indo-European people; "Indo-
       European migrations" [syn: Indo-European, Indo-Aryan,
       Aryan]
    n 1: a member of the prehistoric people who spoke Proto-Indo
         European [syn: Aryan, Indo-European]
    2: the family of languages that by 1000 BC were spoken
       throughout Europe and in parts of southwestern and southern
       Asia [syn: Indo-European, Indo-European language, Indo-
       Hittite]