anastomose is:
to meet and unite or run into each other, coalesce, interjoin.
to form a network or mesh – as in channels or lines of a branching system – rivers & tributaries, leaf veins, blood vessels, nerves.

Etymology: Back-formation from anastomosis: Late Latin anastomosis, from Greek, outlet, from anastomoun, to furnish with a mouth: ana-, ana- + stoma, mouth, opening.