The Collaborative International Dictionary of English v.0.48:

Inarch \In*arch"\, v. t. [imp. & p. p. Inarched; p. pr. & vb.
   n. Inarching.]
   To graft by uniting, as a scion, to a stock, without
   separating either from its root before the union is complete;
   -- also called to graft by approach. --P. Miler.
   [1913 Webster]