The Collaborative International Dictionary of English v.0.48:

Accadian \Ac*ca"di*an\, a. [From the city Accad. See Gen. x.
   10.]
   Pertaining to a race supposed to have lived in Babylonia
   before the Assyrian conquest.
   [1913 Webster] -- Ac*ca"di*an, n., Ac"cad, n. --Sayce.
   [1913 Webster]

Easton's 1897 Bible Dictionary:

Accad
   the high land or mountains, a city in the land of Shinar. It has
   been identified with the mounds of Akker Kuf, some 50 miles to
   the north of Babylon; but this is doubtful. It was one of the
   cities of Nimrod's kingdom (Ge 10:10). It stood close to the
   Euphrates, opposite Sippara. (See SEPHARVAIM.)

     It is also the name of the country of which this city was the
   capital, namely, northern or upper Babylonia. The Accadians who
   came from the "mountains of the east," where the ark rested,
   attained to a high degree of civilization. In the Babylonian
   inscriptions they are called "the black heads" and "the black
   faces," in contrast to "the white race" of Semitic descent. They
   invented the form of writing in pictorial hieroglyphics, and
   also the cuneiform system, in which they wrote many books partly
   on papyrus and partly on clay. The Semitic Babylonians ("the
   white race"), or, as some scholars think, first the Cushites,
   and afterwards, as a second immigration, the Semites, invaded
   and conquered this country; and then the Accadian language
   ceased to be a spoken language, although for the sake of its
   literary treasures it continued to be studied by the educated
   classes of Babylonia. A large portion of the Ninevite tablets
   brought to light by Oriental research consists of interlinear or
   parallel translations from Accadian into Assyrian; and thus that
   long-forgotten language has been recovered by scholars. It
   belongs to the class of languages called agglutinative, common
   to the Tauranian race; i.e., it consists of words "glued
   together," without declension of conjugation. These tablets in a
   remarkable manner illustrate ancient history. Among other
   notable records, they contain an account of the Creation which
   closely resembles that given in the book of Genesis, of the
   Sabbath as a day of rest, and of the Deluge and its cause. (See
   BABYLON; CHALDEA.)


Hitchcock's Bible Names Dictionary (late 1800's):

Accad, a vessel; pitcher; spark