Source : Webster's Revised Unabridged Dictionary (1913)

Terra \Ter"ra\, n. [It. & L. See {Terrace}.]
   The earth; earth.

   {Terra alba} [L., white earth] (Com.), a white amorphous
      earthy substance consisting of burnt gypsum, aluminium
      silicate (kaolin), or some similar ingredient, as
      magnesia. It is sometimes used to adulterate certain
      foods, spices, candies, paints, etc.

   {Terra cotta}. [It., fr. terra earth + cotta, fem. of cotto
      cooked, L. coctus, p. p. of coquere to cook. See {Cook},
      n.] Baked clay; a kind of hard pottery used for statues,
      architectural decorations, figures, vases, and the like.
      

   {Terr[ae] filius} [L., son of the earth], formerly, one
      appointed to write a satirical Latin poem at the public
      acts in the University of Oxford; -- not unlike the
      prevaricator at Cambridge, England.

   {Terra firma} [L.], firm or solid earth, as opposed to
      {water}.

   {Terra Japonica}. [NL.] Same as {Gambier}. It was formerly
      supposed to be a kind of earth from Japan.

   {Terra Lemnia} [L., Lemnian earth], Lemnian earth. See under
      {Lemnian}.

   {Terra ponderosa} [L., ponderous earth] (Min.), barite, or
      heavy spar.

   {Terra di Sienna}. See {Sienna}.

Source : WordNet®

terra alba
     n 1: finely pulverized gypsum used especially as a pigment
     2: fine white clay used in making tobacco pipes and pottery and
        in whitening leather [syn: {pipeclay}]
     3: a fine usually white clay formed by the weathering of
        aluminous minerals (as feldspar); used in ceramics and as
        an absorbent and as a filler (e.g., in paper) [syn: {china
        clay}, {china stone}, {kaolin}, {kaoline}, {porcelain clay}]