The Collaborative International Dictionary of English v.0.48:

Latin \Lat"in\, a. [F., fr. L. Latinus belonging to Latium,
   Latin, fr. Latium a country of Italy, in which Rome was
   situated. Cf. Ladin, Lateen sail, under Lateen.]
   1. Of or pertaining to Latium, or to the Latins, a people of
      Latium; Roman; as, the Latin language.
      [1913 Webster]

   2. Of, pertaining to, or composed in, the language used by
      the Romans or Latins; as, a Latin grammar; a Latin
      composition or idiom.
      [1913 Webster]

   Latin Church (Eccl. Hist.), the Western or Roman Catholic
      Church, as distinct from the Greek or Eastern Church.

   Latin cross. See Illust. 1 of Cross.

   Latin races, a designation sometimes loosely given to
      certain nations, esp. the French, Spanish, and Italians,
      who speak languages principally derived from Latin.

   Latin Union, an association of states, originally
      comprising France, Belgium, Switzerland, and Italy, which,
      in 1865, entered into a monetary agreement, providing for
      an identity in the weight and fineness of the gold and
      silver coins of those countries, and for the amounts of
      each kind of coinage by each. Greece, Servia, Roumania,
      and Spain subsequently joined the Union.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Latin cross
    n 1: a cross with the lowest arm being longer than the others