The Collaborative International Dictionary of English v.0.48:

Lute \Lute\, n. [L. lutum mud, clay: cf. OF. lut.]
   [1913 Webster]
   1. (Chem.) A cement of clay or other tenacious infusible
      substance for sealing joints in apparatus, or the mouths
      of vessels or tubes, or for coating the bodies of retorts,
      etc., when exposed to heat; -- called also luting.
      [1913 Webster]

   2. A packing ring, as of rubber, for fruit jars, etc.
      [1913 Webster]

   3. (Brick Making) A straight-edged piece of wood for striking
      off superfluous clay from mold.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lute \Lute\, v. t. [imp. & p. p. Luted; p. pr. & vb. n.
   Luting.]
   To close or seal with lute; as, to lute on the cover of a
   crucible; to lute a joint.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Luting \Lut"ing\ (l[=u]t"[i^]ng), n. (Chem.)
   See Lute, a cement.
   [1913 Webster]

WordNet (r) 3.0 (2006):

luting
    n 1: a substance for packing a joint or coating a porous surface
         to make it impervious to gas or liquid [syn: lute,
         luting]