anastomosis

A cross-connection between two blood vessels.

An interconnection between any two channels, passages or vessels.

(...) our grandam, which we are linked up with by successive anastomosis of navelcords sold us all, seed, breed and generation, for a penny pippin.

A dark purple fluid appeared to pulse in the tortuous anastomoses of channels which lay under the surface.

The surgical creation of a connecting passage between blood vessels, bowels or other channels.

The insertion of one word within another, as in "underdarkneath" (James Joyce).