The Collaborative International Dictionary of English v.0.48:

Frit \Frit\, v. t. [imp. & p. p. Fritted; p. pr. & vb. n.
   Fritting.]
   To prepare by heat (the materials for making glass); to fuse
   partially. --Ure.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fritting \Frit"ting\, n. [See Frit to expose to heat.]
   The formation of frit or slag by heat with but incipient
   fusion.
   [1913 Webster]